Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/19/14


AREA FORECAST DISCUSSION
NWS TUCSON AZ
935 AM MST SUN AUG 17 2014 .SYNOPSIS...AMPLE MOISTURE WILL PROVIDE SCATTERED THUNDERSTORMS THIS WEEK. SOME STORMS WILL PRODUCE GUSTY WINDS AS WELL AS HEAVY RAIN THAT MAY LEAD TO FLASH FLOODING. && .DISCUSSION...ISOLATED SHOWERS WERE OCCURRING IN AN ARC FROM ORACLE TO PICACHO PEAK TO JUST WEST OF SELLS. THE REST OF SE AZ WAS PRECIP-FREE AT THIS TIME. IR/VISIBLE SATELLITE IMAGERY INDICATED MOSTLY SUNNY SKIES ACROSS FAR ERN SECTIONS...AND PARTLY CLOUDY TO MOSTLY CLOUDY SKIES ELSEWHERE. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z RANGED FROM THE UPPER 50S-MID 60S F...AND THESE TEMPS WERE GENERALLY 2-5 DEGS F LOWER VERSUS 24 HOURS AGO. SURFACE TEMPS FROM TUCSON WWD VALID 16Z WERE ABOUT 3-8 DEGS F COOLER VERSUS 24 HOURS AGO. SURFACE TEMPS ELSEWHERE WERE NEARLY IDENTICAL TO THIS TIME SAT. 1501Z BLENDED TOTAL PRECIP WATER PRODUCT YIELDED VALUES RANGING FROM AROUND 0.75 INCHES ACROSS THE WHITE MOUNTAINS TO NEARLY 1.40 INCHES ACROSS WRN PIMA COUNTY. 17/12Z UPPER AIR PLOTS DEPICTED BROAD RIDGE OVER THE SWRN CONUS WITH 594 DM HIGH PRESSURE CENTERED OVER NERN AZ. LIGHT GENERALLY ELY MID-LEVEL STEERING FLOW PREVAILED OVER SE AZ. THE ISOLATED SHOWERS ACROSS WRN SECTIONS ARE EXPECTED TO MOVE WWD AND WEAKEN DURING THE NEXT 1-2 HOURS AS PER THE 17/14Z RUC HRRR AND 17/12Z NAM SOLUTIONS. SCATTERED SHOWERS/TSTMS SHOULD DEVELOP BY EARLY THIS AFTERNOON ACROSS THE HIGHER TERRAIN OF GREENLEE/GRAHAM/ COCHISE COUNTIES. THESE SHOWERS/TSTMS WILL THEN MOVE WWD THIS AFTERNOON AND INTO THIS EVENING. THERE ARE SOME DIFFERENCES BETWEEN THE NAM...RUC HRRR...AND UNIV OF AZ WRF-NAM REGARDING THE WWD EXTENT OF CELL MIGRATION INTO THIS EVENING. HOWEVER...THESE SOLUTIONS ARE SIMILAR WITH LIMITING ANY RAINFALL OF SIGNIFICANCE MOSTLY TO AREAS EAST OF TUCSON THIS AFTERNOON. APPEARS THAT SHOWERS/TSTMS THAT OCCURRED LAST NIGHT ACROSS ERN PIMA COUNTY WERE SUFFICIENT TO INHIBIT CONVECTIVE DEVELOPMENT THIS AFTERNOON. THUS...FORECAST CONFIDENCE IS SUFFICIENTLY HIGH AT THIS TIME TO LOWER POPS FOR THE TUCSON METRO AREA AND ADJACENT LOWER ELEVATION LOCALES THIS AFTERNOON. THE OFFICIAL FORECAST WILL BE UPDATED TO REFLECT THIS SCENARIO. WILL ALSO FAVOR THE DRIER RUC HRRR SOLUTION TO REDUCE POPS ACROSS WRN SECTIONS THIS AFTERNOON. OTHERWISE...SCATTERED SHOWERS/TSTMS WILL OCCUR THIS AFTERNOON ACROSS ERN SECTIONS. THE MAIN IMPACTS WILL BE LOCALLY HEAVY RAINFALL AND BRIEF STRONG WIND GUSTS. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 18/18Z. SCATTERED -TSRA/-SHRA WILL DEVELOP ACROSS THE HIGHER TERRAIN EAST OF KTUS BY EARLY THIS AFTERNOON. THESE SHOWERS/THUNDERSTORMS WILL THEN MOVE WWD ACROSS SE AZ THRU THIS EVENING AND LATER TONIGHT. THE BULK OF ANY -TSRA/-SHRA IS THEN EXPECTED TO BE WEST OF KTUS MONDAY MORNING. MVFR VISIBILITIES AND BRIEF WIND GUSTS TO NEAR 50 KTS WILL OCCUR WITH THE STRONGER TSRA. OTHERWISE...CLOUD DECKS WILL MAINLY BE AT 6-12K FT AGL AND SURFACE WIND WILL GENERALLY BE LESS THAN 10 KTS THRU MONDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...SCATTERED THUNDERSTORMS WILL OCCUR THIS WEEK AS AMPLE MOISTURE REMAINS ACROSS SOUTHEAST ARIZONA. THE STRONGER THUNDERSTORMS WILL PRODUCE STRONG...GUSTY AND ERRATIC WINDS. OTHERWISE...AFTERNOON MINIMUM RELATIVE HUMIDITIES ARE FORECAST TO BE MOSTLY IN THE 25-40 PERCENT RANGE AT LOWER ELEVATIONS FOLLOWED BY GOOD TO EXCELLENT OVERNIGHT RECOVERIES. 20-FOOT WINDS WILL EXHIBIT NORMAL DIURNAL TRENDS AND BE MOSTLY LESS THAN 15 MPH. && .PREV DISCUSSION...MONDAY...E-SE FLOW ALOFT WITH UPPER HIGH OVER NRN NM. PRECIPITABLE WATER VALUES ARE FORECAST TO BE A TICK WETTER THAN TODAY. LOOKING AT ANOTHER ROUND OF SCATTERED STORMS WITH A FEW LINGERING INTO THE OVERNIGHT HOURS. FURTHER UPSTREAM ON MONDAY AN UPPER LEVEL TROF WHICH IS OVER THE PACIFIC NW TODAY...WILL DROP INTO NRN CA AND DEVELOP INTO A CLOSED LOW OFF NRN CA CST. THIS FEATURE WILL BE A PLAYER IN OUR FORECAST LATER IN THE WEEK. TUESDAY...SOUTHERLY FLOW INCREASES AS THE ABOVE MENTIONED NRN CA UPPER LOW DROPS S ALONG THE CA CST AND BE OFF LA BASIN LATE IN THE AFTERNOON. PRECIPITABLE WATER VALUES ARE FORECAST TO BE IN THE 1.50"-1.80" RANGE. CHAOS REIGNS FOR THE REMAINDER OF THE WEEK WITH RESPECT TO WHERE THE ABOVE MENTIONED CUT-OFF LOW WILL MOVE AND HOW MUCH THE TROPICS START TO BE PLAYER. AT THIS TIME...AND WITH THE MEDIUM RANGE MODELS ALONG WITH THE ENSEMBLES HAVE MANY SOLUTIONS...HAVE DECIDED TO GO WITH CLIMO POPS ACROSS THE AREA STARTING WEDNESDAY THROUGH SATURDAY. SURE LOOKS LIKE IT WILL BE A WET WEEK ACROSS SE ARIZONA. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS PREVIOUS DISCUSSION...GLUECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
823 PM MDT MON AUG 18 2014 .UPDATE... ISSUED AT 820 PM MDT MON AUG 18 2014 UPDATED MOST POP FORECASTS, REMOVING POPS OVER THE PLAINS AND EASTERN MOUNTAINS, WHILE ADDING/EXTENDING PRECIP CHANCES OVER THE SOUTHWEST MOUNTAINS AND SAN LUIS VALLEY...AS AREA OF TSRA OVER THE SAN JUANS WILL MOVE EAST ACROSS LOWER ELEVATIONS BEFORE ENDING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 259 PM MDT MON AUG 18 2014 THE UPR RIDGE IS STILL CENTERED NR THE FOUR CORNERS AREA TODAY AND PRECIPITABLE WATER VALUES ARE SIMILAR TO WHAT THEY WERE YESTERDAY. ISOLATED SHOWERS AND TSTMS HAVE DEVELOPED OVR SOME OF THE MOUNTAIN AREAS AS OF 1930Z. SHOULD SEE COVERAGE OVR THE MTNS INCREASE THIS AFTERNOON. HRRR AND RAP SHOW PCPN DEVELOPING/MOVING OVR THE SERN PLAINS AND PORTIONS OF THE SAN LUIS VALLEY LATER THIS AFTERNOON AND THIS EVENING. THE HRRR AND RAP HAVE PCPN ENDING IN MOST LOCATIONS BY LATE EVENING...BUT SHOW THE POTENTIAL FOR SOME CONTINUING OVR THE SAN JUAN MTNS INTO THE LATE NIGHT HOURS. AS AN UPR TROF DIGS INTO SRN CA TONIGHT AND TUESDAY...THE UPR RIDGE OVR OUR AREA SHIFTS EASTWARD. THIS PUSHES A LITTLE BETTER MSTR INTO WRN CO FOR TUE...WITH PRECIPITABLE WATER VALUES INCREASING SLIGHTLY OVR THE CONTDVD. AS A RESULT THERE SHOULD BE MORE WIDESPREAD SHOWER AND TSTM ACTIVITY ALONG THE CONTDVD TOMORROW. THE ERN MTNS WL LIKELY SEE SCT PCPN DEVELOPING IN THE AFTERNOON HOURS...WHILE THE SERN PLAINS SHOULD JUST SEE A FEW SHOWERS OR STORMS DEVELOP. HIGH TEMPS ON TUE SHOULD BE 5-8 DEGREES ABOVE AVERAGE OVR THE SERN PLAINS...AND AROUND NORMAL IN THE SAN LUIS VALLEY AND UPR ARKANSAS RIVER VALLEY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 259 PM MDT MON AUG 18 2014 ...ACTIVE WEATHER FOR AT LEAST THE NEXT WEEK... MODELS ARE NOW IN REASONABLE AGREEMENT THAT THE CUTOFF LOW OFF THE CA COAST WILL PHASE WITH THE TROUGH MOVING INTO THE PACNW...AND THIS WILL LEAD TO AN ENHANCED MONSOONAL PATTERN FOR THE LATTER PART OF THIS WEEK AND BEYOND. A COUPLE OF ADDITIONAL SHORTWAVES WILL MOVE THROUGH THE LONGWAVE TROUGH PATTERN THAT IS OVER WRN CANADA...BRINGING THE THREAT FOR PERIODS OF HEAVY RAIN TO OUR AREA. TUE NIGHT...EXPECT ISOLD STORMS TO PERSIST OVER THE CONTDVD AS THE PLUME BEGINS TO MOVE OVR WRN CO. BY LATE WED THE TROUGH AND ABSORBED CUTOFF WILL MOVE INTO NW AZ/SW UT...AND THE THREAT OF HEAVY BANDS OF CONVECTION WILL CONTINUE FOR THE SW MTS AND CONTDVD. DEPENDING ON WHAT HAS ALREADY FALLEN OVR THE MTS WE COULD SEE THE THREAT OF MORE FLASH FLOODING AND RISK OF SLIDES FOR THE MT AREAS. TIMING FOR OUR CWA`S STAGES IN THE PRO CYCLING CHALLENGE DOES NOT LOOK FAVORABLE AS THE STRONGEST DYNAMICS FROM THIS SYSTEM MOVE THROUGH ON THURSDAY. THAT IS WHEN THE CORE OF A 100 KT JET STREAK MOVES THROUGH CO. THIS IS PRETTY ROBUST FOR AN AUGUST SYSTEM. WITH H6 TEMPS AT MINUS 2C OR LOWER IN THE CORE OF THE LOW...COULD EASILY SEE SOME SNOW FOR ELEVS ABOVE 12K FEET BY FRI MORNING. THE GFS BRINGS US A BIT OF A BREAK IN THE ACTION ON SATURDAY BEFORE ANOTHER FRONT COMES THROUGH SAT NIGHT...FOLLOWED BY A THIRD SYSTEM SUN OR MON. THE ECMWF HAS SOME OF THE HEAVIEST QPF ON FRI AND CONTINUES THE ONSLAUGHT THROUGH THE WEEKEND. A BIT HARD TO SAY WHEN THE HEAVIEST RAIN WILL FALL...BUT THE THREAT OF HEAVY PRECIP WILL CERTAINLY BE WITH US SO LONG AS THIS PARADE OF SHORTWAVES CONTINUE...AT LEAST THROUGH THE FIRST DAYS OF NEXT WEEK. ENSEMBLE POPS LOOKED MUCH TOO LOW SO HAVE RAISED POPS BY AT LEAST 10 PERCENT OVER THIS TIME FRAME FOR BOTH THE PLAINS AND MTS...WHILE THE MTS WILL SEE THE BEST SHOT AT HEAVY PRECIP. TEMPS WILL TREND DOWNWARD THROUGH THE PERIOD...STARTING IN THE NR 90 RANGE FOR TUE-THU...AND THEN FALLING INTO THE 80S AND POSSIBLY LOWER FOR THE PLAINS NEXT WEEKEND. LOOKS LIKE THE FORECAST WILL REMAIN CHALLENGING FOR THE REST OF THIS MONTH. ROSE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 259 PM MDT MON AUG 18 2014 VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS TONIGHT THROUGH TUESDAY AFTERNOON. TSTMS COULD MOVE INTO THE VCNTY OF THE TERMINAL SITES THIS EVENING...WITH KCOS SEEING THE BEST CHANCE OF THIS OCCURRING. SHOWERS AND TSTMS WL AGAIN DEVELOP OVR THE MOUNTAINS AND THEN SPREAD OVR SOME OF THE LOWER ELEVATIONS...POSSIBLY MOVING IN THE VCNTY OF THE TERMINAL SITE. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PETERSEN SHORT TERM...28 LONG TERM...ROSE AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
523 PM MDT MON AUG 18 2014 .SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT) ISSUED AT 333 PM MDT MON AUG 18 2014 BIG CHANGES WILL OCCUR OVER THE NEXT 24 HOURS AS AN UNSEASONABLY STRONG AND NEARLY VERTICALLY STACKED TROUGH...CURRENTLY OVER CALIFORNIA...MOVES EAST INTO THE GREAT BASIN. THIS BRINGS EASTERN UTAH AND WESTERN COLORADO INTO IDEAL POSITION FOR DEEP SUBTROPICAL MOISTURE TO ADVECT INTO THE REGION. PRECIPITABLE WATER VALUES OF 1 TO 1.3 INCH ARE EXPECTED TO COVER EASTERN UTAH AND EVEN EXTREME WESTERN COLORADO BY LATE TUESDAY AFTERNOON. THIS IS ALMOST 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. MODELS ARE FORECASTING MULTIPLE VORT MAXES TO REACH THE UT/CO BORDER THROUGHOUT THE DAY FROM NOON TO MIDNIGHT. THERE IS SOME UNCERTAINTY ON THE TIMING OF H3 JET SUPPORT OF 60KTS REACHING THE AREA...WHICH WILL HELP TO PROVIDE ASCENT IN THE UNIMPRESSIVE CAPE AND SHEAR ENVIRONMENT. EXPECTING CLOUD COVER TO HINDER INSTABILITY DURING THE DAY...HOWEVER THIS SCENARIO COULD CHANGE IF SUFFICIENT CLEAR AIR IS ABOUND BY LATE MORNING. THE RAP SHOWS JET SUPPORT INCHING INTO EASTERN UTAH AND SOUTHWEST COLORADO DURING THE MORNING ON TUESDAY...HOWEVER THE NAM AND GFS SHOW THE BEST JET SUPPORT ON TUESDAY NIGHT AND WEDNESDAY MORNING. STORM MOTION WILL BE DECENT FOR TUESDAY - ABOUT 20 TO 30 KTS...SO COULD NOT JUSTIFY A FLASH FLOOD WATCH AT THIS TIME. IT WILL RAIN IN MANY LOCATIONS BY TUESDAY NIGHT...BUT ONLY EXPECTING MODERATE TO HEAVY RAIN MULTICELLULAR STORMS CAUSING NUISANCE/SMALL STREAM FLOODING AT THIS TIME. SEE HYDRO SECTION FOR MORE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 333 PM MDT MON AUG 18 2014 THE FORECAST AREA REMAINS UNDER SW FLOW WED-THU WITH THE JET AXIS OVERHEAD. MONSOONAL MOISTURE PLUME WEAKENS WITH PRECIPITABLE WATER VALUES DROPPING UNDER 1 INCH. NAM/GFS SHOW A WEAK 300 MB JET MAX ARRIVING ON WED FOR POTENTIAL SUPPORT AND INCREASED VERTICAL SHEAR....AND SHOULD IT ENTRAIN SOME DRIER MIDLEVEL AIR OVER HIGHER MOISTURE NEAR THE SURFACE...IT COULD LEAD TO SOME STRONGER STORMS WED AFTERNOON. MODELS STILL HAVING TROUBLE HANDLING THE UPPER LOW THAT IS CURRENTLY DROPPING SOUTH ALONG THE NRN CA COAST...WHICH LOWERS FORECAST CONFIDENCE AFTER MIDWEEK. BUT AT LEAST THE GFS AND ECWMF NOW BOTH BRING THE 500 MB LOW INLAND...JUST TIMING AND TRACK ARE DIFFERENT. THE 12Z GFS SWINGS THE LOW INLAND ACROSS SRN CA WED AND THEN LIFTS IT NE ACROSS UT AS AN OPEN WAVE ON THU. THIS COULD ADD SOME DYNAMIC PUNCH TO STORM DEVELOPMENT ON THU. THE 12Z ECMWF IS SLOWER BRINGING IT INLAND AND TRACKS IT FARTHER SOUTH ACROSS AZ AND NWRN NM. THE 12Z CANADIAN HAS IT SHEARING OUT ALONG THE SRN CA COAST THU-FRI. MODELS ALSO SHOW ENERGY DROPPING OUT OF THE GULF OF AK LATE IN THE WEEK THAT SHOULD MAINTAIN TROUGHING OVER THE PAC NW/NRN ROCKIES. FOR NOW...WITH FOLLOW THE CONSENSUS MODEL TREND...WHICH SHOWS A LESSENING OF STORM COVERAGE THE LAST HALF OF THE WEEK BUT NOT A COMPLETE CESSATION. LOWER LEVEL MOISTURE LIKELY TO LINGER WITH SOME SMALLER EMBEDDED WAVES IN THE FLOW THAT COULD TRIGGER ISOLATED- SCATTERED ACTIVITY ABOUT EACH DAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 519 PM MDT MON AUG 18 2014 MOST CONVECTION IS EXPECTED TO DIE DOWN OVERNIGHT THOUGH SOME LINGERING SHOWERS...MAYBE A QUICK RUMBLE OF THUNDER...IS POSSIBLE THROUGH 09Z. FLYING CONDITIONS WILL DETERIORATE TOMORROW AS A DISTURBANCE MOVES OVERHEAD WITH MID LEVEL BKN TO OCCNL OVC CIGS EXPECTED FROM 18Z ONWARDS. MANY AREAS WILL SEE VCSH BECOMING VCTS AS THE AFTERNOON PROGRESSES. THE STRONGER CELLS WILL PRODUCE MVFR TO POSSIBLY IFR VIS AT TIMES DUE TO LOWERED VISIBILITIES. GUSTY OUTFLOW WINDS ARE ALSO POSSIBLE REACHING 40+ MPH IN THE AFTERNOON AND EVENING HOURS. MTN TOPS WILL LIKELY BE OBSCURED FOR MOST OF THE FORECAST AREA. CONVECTION IS EXPECTED TO CONTINUE OVERNIGHT THOUGH COVERAGE WILL LESS THAN SEEN DURING THE DAY. && .HYDROLOGY... ISSUED AT 333 PM MDT MON AUG 18 2014 MONSOONAL MOISTURE WILL RETURN TOMORROW AS AN UPPER LEVEL LOW OVER CALIFORNIA PULLS DEEP SUBTROPICAL MOISTURE INTO THE REGION. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE FROM WEST TO EAST THROUGHOUT THE AFTERNOON AND PEAK DURING THE LATE HOURS OF THE DAY AND OVERNIGHT INTO WEDNESDAY MORNING. EXPECTING TO HAVE SMALL STREAM AND ARROYO FLOOD ISSUES BY WEDNESDAY MORNING IN THE USUAL PROBLEM AREAS...BUT AT THIS NOT EXPECTING HIGH COVERAGE OF TORRENTIAL DOWNPOURS DUE TO THUNDERSTORMS. THEREFORE...NO WATCHES HAVE BEEN ISSUED AT THIS TIME. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JAM LONG TERM...JAD AVIATION...TGR HYDROLOGY...JAM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
316 PM MDT SUN AUG 17 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 252 PM MDT SUN AUG 17 2014 AN UPR RIDGE WL REMAIN CENTERED NR THE FOUR CORNERS THRU TONIGHT...SHIFTING A LITTLE EASTWARD ON MON. THIS AFTERNOON A WEAK DISTURBANCE IS MOVING ACRS NRN CO. SOME ISOLD THUNDERSTORMS HAVE DEVELOPED OVR SOME OF THE MTN AREAS AND OVER THE EAST CENTRAL PLAINS. EXPECTING MORE DEVELOPMENT OVR THE MTNS THE REST OF THIS AFTERNOON...WITH SOME ISOLD DEVELOPMENT OVR PORTIONS OF THE SERN PLAINS. BOTH THE RAP AND HRRR CONTINUE TO SHOW AN AREA OF TSTMS DEVELOPING THIS AFTERNOON...ASSOCIATED WITH THE WX DISTURBANCE... OVER THE PIKES PEAK REGION AND THEN MOVING SOUTHEASTWARD ACRS THE SERN PLAINS THRU THE EVENING HOURS...AND DISSIPATING OR EXITING THE SERN CORNER OF THE STATE BY ABOUT 1 OR 2 AM. ON MONDAY AN UPR TROF MOVES INTO WRN NV AND SHIFT THE UPR RIDGE CENTER A LITTLE EASTWARD OVR CO. PRECIPITABLE WATER VALUES ACRS THE FORECAST AREA ARE EXPECTED TO BE SIMILAR TO TODAY. EXPECTING SOME SHOWERS/TSTM DEVELOPMENT OVR SOME OF THE MTN AREAS IN THE LATE MORNING HOURS AGAIN. THEN INCREASING IN COVERAGE IN THE AFTERNOON HOURS OVER THE MTNS AND HIGH VALLEYS...WITH SOME ISOLD STORMS DEVELOPING OVR MOVING OVR THE SOUTHEAST PLAINS. HIGH TEMPS ON MON WL AGAIN BE ABOVE AVERAGE BY AROUND 5 DEGREES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 252 PM MDT SUN AUG 17 2014 ...MORE MONSOON NEXT WEEK... EXTENDED FORECAST CONTINUES TO BE A BIT SHAKY AS THE GLOBAL MODEL RUNS STRUGGLE WITH FAIRLY COMPLEX INTERACTIONS INVOLVING THE POLAR JET TO THE NORTH AND A SUBTROPICAL INFLUENCE TO THE SOUTH. THE EC AND GFS ARE IN REASONABLE AGREEMENT THROUGH ABOUT TUESDAY...THEN THE CONSISTENCY STARTS TO UNRAVEL. A PACIFIC TROUGH WILL AMPLIFY ON TUESDAY AND BEGIN MOVING INTO THE PACNW...AS A CUTOFF LOW DRIFTS OFF THE CA COAST. INCREASED S-SW FLOW ALOFT WILL BRING MOISTURE UP FROM MEXICO AND THE DESERT SW INTO WRN CO. THE ECMWF SEEMS TO BE OVERDOING QPF E OF THE MTS...WHILE THE GFS AND NAM ARE MORE REALISTIC IN DEPICTING MOSTLY DRY CONDITIONS FOR THE PLAINS BUT PLENTY OF MOISTURE FOR THE MTN AREAS. TEMPS WILL START TO MODERATE FOR MOST OF OUR CWA AND SHOULD BE CLOSE TO AVERAGE. THE LATEST GFS HAS A STRONGER OR MORE AMPLIFIED NRN TROUGH...AND ALSO SHOWS BETTER PHASING WITH THE CA CUT-OFF LOW. IT ALSO HINTS AT AT LEAST A POTENTIAL MOISTURE TAP FROM A TROPICAL SYSTEM THAT WILL BE MOVING NWD...WELL OFF OF THE BAJA PENINSULA. THE EC HAS A WEAKER NRN SYSTEM AND RETROGRADES THE UPPER LOW AND TROPICAL SYSTEM OFF THE CA COAST...WITH LESS OF A MOISTURE FLUX INTO CO. BASED ON THE PATTERN AND ENSEMBLE TRENDS...IT APPEARS LIKELY THAT AN AMPLIFIED PACIFIC SYSTEM WILL MOVE INTO THE NRN ROCKIES FOR THE LATTER PART OF NEXT WEEK INTO NEXT WEEKEND. HAVE BOOSTED POPS FROM WED ONWARD BY 5-10 PERCENT TO ACCOUNT FOR THAT LIKELIHOOD...AND LATER SHIFTS MAY HAVE TO CONTINUE THAT TREND IF THE DEEPER SYSTEM ENDS UP LOOKING MORE LIKELY. WILL HAVE TO KEEP A CLOSE EYE ON TRENDS...SINCE THE LONG RANGE GFS HINTS AT SIGNIFICANT RAINFALL POSSIBLE ON THE BACKSIDE OF THIS NRN BRANCH SYSTEM...BY THE LAST WEEK IN AUGUST. ROSE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 252 PM MDT SUN AUG 17 2014 EXPECTING VFR CONDITIONS AT KCOS...KPUB AND KALS TONIGHT THROUGH MONDAY AFTERNOON. SOME TSTMS MAY MOVE INTO THE VCNTY OF THE TERMINAL SITES THIS EVENING WITH GUSTY WINDS BEING THE MAIN THREAT. ON MONDAY...GENERALLY AFTER 20Z THERE MAY AGAIN BE SOME TSTMS IN THE VCNTY OF THE TERMINAL SITES. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...ROSE AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1122 PM MDT SAT AUG 16 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 236 PM MDT SAT AUG 16 2014 AN UPR RIDGE WL REMAIN CENTERED OVR NORTHERN AZ TONIGHT AND SUNDAY. THIS AFTERNOON...WV SATELLITE IMAGERY SHOWING DRIER AIR PUSHING EASTWARD ACRS THE STATE. HOWEVER THERE IS STILL ENOUGH MSTR OUT THERE...THAT WITH THE AFTERNOON INSTABILITY...ISOLATED SHOWERS/TSTMS HAVE DEVELOPED OVR THE SERN PLAINS WHERE THE MSTR IS A LITTLE BETTER...AND ISOLATED TO SCATTERED CONVECTION HAS DEVELOPED OVR THE MTNS. WILL KEEP ISOLD TO SCT SHOWERS/TSTMS IN THE FORECAST ACRS THE AREA THRU THE EVENING HOURS...THEN SHOULD SEE DECREASING PCPN CHANCES AFTER SUNSET. THE RAP AND HRRR SHOW ALL PCPN ENDING BY MIDNIGHT. THE NAM KEEPS SOME PCPN GOING ACRS MAINLY THE SEN PLAINS INTO THE LATE NIGHT. FOR NOW HAVE DECIDED TO GO WITH RAP AND HRRR AND END ALL PCPN BY MIDNIGHT IN THE FORECAST. THE NAM SHOWS SLIGHTLY LOWER PRECIPITABLE WATER VALUES ACRS THE FORECAST AREA ON SUN...BUT THERE WL STILL BE ENOUGH MSTR AND INSTABILITY FOR SHOWERS AND TSTMS TO DEVELOP. IT SHOULD START OVR THE MTNS IN THE LATE MORNING/EARLY AFTERNOON HOURS WITH ISOLD TO SCT COVERAGE IN THE AFTERNOON AND EVENING HOURS. SOME ISOLATED SHOWERS/STORMS SHOULD DEVELOP OVR THE SERN PLAINS IN THE AFTERNOON AS WELL. HIGH TEMPS ON SUN WL AGAIN BE A LITTLE ABOVE AVERAGE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 236 PM MDT SAT AUG 16 2014 ...MONSOON CONTINUES THROUGH NEXT WEEK... THE TYPICAL SUMMER MONSOON WE HAVE BEEN DEALING WITH LOOKS TO CONTINUE THROUGH NEXT WEEK. THE UPPER HIGH TO OUR SW WILL SHIFT INTO ERN OK/TX AS A TROUGH OVER THE PACNW ADVANCES EWD...AND THIS WILL KEEP A STEADY STREAM OF SUBTROPICAL MOISTURE OVER OUR AREA. SUN NIGHT...MODELS HAVE BEEN VERY CONSISTENT IN DEVELOPING A LINE/CLUSTER OF STORMS OVER E-CENTRAL CO BY EARLY EVENING IN A WEAK BAROCLINIC ZONE. THIS MCS WILL SHIFT SLOWLY SWD DURING THE EVENING. EXPECT THE HEAVIEST QPF TO BE OVER ERN AL PASO AND KIOWA COUNTIES. SHOULD CLEAR OUT AFTER MIDNIGHT. MONDAY...WEAK UPSLOPE WILL PROVIDE AN EXTRA TRIGGER FOR MORE PM STORMS...PROBABLY A BIT MORE COVERAGE OVER THE PLAINS THAN ON PRECEDING DAYS. IT WILL BE ANOTHER VERY WARM DAY WITH SOME MID 90S OVER THE HOT SPOTS ON THE PLAINS. BY TUESDAY...WILL START TO SEE INCREASING MOISTURE MOVE NWD OVER WRN CO AS A CUTTOFF DROPS ACROSS THE SRN CA COAST AND THE PACNW TROUGH BEGINS MOVING INLAND. STILL SOME UNCERTAINTY ON HOW WELL THE CUTOFF WILL PHASE WITH THE NRN JET BRANCH...AND THIS WILL AFFECT HOW MUCH RAIN TO EXPECT OVER OUR AREA NEXT WEEK INTO NEXT WEEKEND. HOWEVER...IT APPEARS LIKELY THAT THERE WILL BE INCREASING SRLY FLOW AHEAD OF THE PACNW TROUGH...WHICH WILL LEAD TO INCREASING HEAVY RAIN CONCERNS FOR THE CENTRAL MTS/CONTDVD TUE- WED...AND THEN THE ERN RANGES AND POSSIBLY PLAINS BY LATE IN THE WEEK. IF THE CUTOFF GETS PICKED UP SOONER BY THE ADVANCING TROUGH...WE COULD SEE ENHANCED PRECIP OVER OUR WHOLE CWA. THE LATEST 12Z ECMWF IS MUCH MORE AGGRESSIVE WITH PHASING THE LOW AND PACNW TROUGH...AND WOULD BRING SIGNIFICANT PRECIP TO OUR AREA FOR THE LATTER PART OF THE WEEK. FOR NOW...WILL STAY THE COURSE WITH CONSERVATIVE LOW POPS FOR THE PLAINS AND TYPICAL SCT/CHANCE POPS FOR THE MTS. WILL HAVE TO SEE HOW THINGS GO OVER THE NEXT COUPLE OF DAYS...BUT IT BEARS WATCHING FOR THE POTENTIAL OF MORE FLOODING...PARTICULARLY FOR THE MTS. ROSE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1116 PM MDT SAT AUG 16 2014 VFR CONDITIONS ALL TAF SITES TONIGHT AND THROUGH THE DAY SUNDAY. ISOLATED TSRA WILL DEVELOP OVER THE MOUNTAINS BUT DOUBTFUL THEY WILL SURVIVE LONG ENOUGH TO REACH KPUB OR KALS. MAY SEE A FEW TSRA ALONG THE PALMER DIVIDE AND EASTWARD TOWARD KLIC SUN AFTERNOON...AND WHILE NO VCTS MENTION IN THE KCOS TAF YET...STORMS MAY BE JUST NORTH OF KCOS FOR A BRIEF TIME AROUND 00Z. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...ROSE AVIATION...PETERSEN
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
936 PM EDT MON AUG 18 2014 .UPDATE... HAVE MADE SEVERAL CHANGES TO POPS THROUGH THE EVENING TO ACCOUNT FOR TRENDS. MOST CONVECTION IS DYING OFF NOW...WITH ONLY LIGHT RAIN REMAINING...BUT THE LEFTOVER MISSISSIPPI VALLEY MCV IS WORKING ITS WAY ACROSS NORTHERN ALABAMA AT AFD TIME AND SHOULD PUSH INTO NORTH GEORGIA IN THE NEXT FEW HOURS. AGAIN HAVE TRIED TO ADJUST POPS TO ACCOUNT FOR THIS. AIRMASS IS PRETTY STABLE BEHIND CONVECTION THIS EVENING SO THINK SEVERE POTENTIAL WITH ANY MCV CONVECTION WOULD BE PRETTY LOW...HEAVY RAIN WOULD BE THE MORE SIGNIFICANT THREAT. UPDATED PRODUCTS OUT SHORTLY. TDP && .PREV DISCUSSION... /ISSUED 750 PM EDT MON AUG 18 2014/ PREV DISCUSSION... /ISSUED 320 PM EDT MON AUG 18 2014/ SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... STALLED FRONTAL BOUNDARY STRETCHES FROM THE TN VALLEY TO THE SOUTHERN MID ATLANTIC STATES. A HIGH PRESSURE RIDGE IS SITUATED ACROSS NORTHERN FL. 500MB ANALYSIS AND WV LOOP SHOWS A POTENT SHORTWAVE MOVING EAST ACROSS NORTHERN MS. THIS FEATURE WILL BE THE FOCUS FOR LATE AFTERNOON AND EVENING CONVECTION ACROSS THE CWFA. THE 16Z HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION THIS AFTERNOON. HAVE TRIED TO ORIENT THE POPS ACCORDING TO CURRENT RADAR TRENDS AND CLOSE TO THE HRRR SOLUTION. GOOD INSTABILITY DOES EXIST AT THE SURFACE...BUT LAPSE RATES REMAIN POOR UNTIL THE COLD POOL ALOFT MOVES OVERHEAD. BY THE TIME THE SHORTWAVE NEARS THE CWFA...INSTABILITY HAS DECREASED WITH THE LOSS OF HEATING. HOWEVER...WITH UNIDIRECTIONAL FLOW...STORMS MAY MOVE REPEATEDLY OVER THE SAME AREAS...WITH LOCALLY HEAVY RAINFALL POSSIBLE. AREAS TO THE NORTH RECEIVED ONE TO TWO INCHES OF RAINFALL OVERNIGHT/EARLY THIS MORNING...SO ANY TRAINING STORMS OR HEAVY RAINFALL MAY CAUSE SOME LOCALIZED FLOODING. BY EARLY TUESDAY...THE POTENT EVENING/OVERNIGHT SHORTWAVE WILL HAVE MOVED OFF TO THE EAST. MODELS ARE PROGGING ANOTHER...WEAKER... SHORTWAVE TO MOVE EAST IN THE FLOW TOMORROW. CONFIDENCE IS LOW ON EXACTLY WHERE CONVECTION WILL DEVELOP TOMORROW. NLISTEMAA LONG TERM /WEDNESDAY THROUGH MONDAY/... LONG TERM FORECAST IS ON TRACK AND HAVE NOT MADE SIGNIFICANT ADJUSTMENTS. ONE ADDITIONAL POINT TO NOTE IS THAT HEAT INDEX VALUES ARE CREEPING ABOVE 100 DEGREES SOUTH OF AN ATLANTA TO ATHENS LINE...WITH PORTIONS OF CENTRAL GEORGIA APPROACHING 105 DEGREES DURING THE SECOND HALF OF THE WEEK. IF THIS TREND CONTINUES...MAY NEED A HEAT ADVISORY FOR THESE 105-108 DEGREE VALUES ACROSS THE SOUTHEAST PART OF THE CWA. 11/ATWELL LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... 00Z GFS AND ECMWF ARE IN UNCOMMONLY GOOD AGREEMENT THROUGH THE EXTENDED FORECAST PERIOD AND CONTINUE THE RECENT TREND OF BUILDING UPPER-LEVEL HIGH PRESSURE INTO THE CENTRAL GULF COAST REGION AND LOWER MISSISSIPPI VALLEY FROM MID-WEEK THROUGH NEXT WEEKEND. BY THE WEEKEND THE UPPER RIDGE IS QUITE STRONG...BUT GEORGIA REMAINS ON THE EASTERN PERIPHERY. THIS SHOULD ALLOW VERY WARM TEMPERATURES AND INHIBIT DIURNAL CONVECTION SOMEWHAT...BUT I DO NOT BELIEVE THE FORECAST AREA IS CLOSE ENOUGH TO THE CENTER OF THE RIDGE TO ELIMINATE POPS ALTOGETHER. 20 AVIATION... 00Z UPDATE... AREA OF TSRA AFFECTING MOST TAF SITES THIS EVENING...THOUGH SHOULD SEE A DIMINISHING TREND OVER THE NEXT FEW HOURS. EXPECT TO SEE MVFR CIGS DEVELOP OVERNIGHT AND CANNOT RULE OUT BRIEF IFR CIGS. CLEARING TOMORROW MORNING BUT HAVE INCLUDED PROB30 DURING THE AFTERNOON TO COVER CHANCE OF CONVECTION. WINDS W THROUGH THE PERIOD GENERALLY BETWEEN 5-10KT THOUGH VRB AND GUSTY IN TSRA THIS EVENING...AND LOW END GUSTS TUESDAY. //ATL CONFIDENCE...00Z UPDATE... HIGH ON CONVECTION TONIGHT...MEDIUM ON TIMING OF CLEARING. MEDIUM ON EARLY MORNING CIGS...LOW ON POTENTIAL IFR DEVELOPMENT. HIGH ON ALL OTHER ELEMENTS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 91 72 97 / 60 40 30 10 ATLANTA 72 88 73 94 / 60 40 30 10 BLAIRSVILLE 66 84 67 90 / 60 40 30 20 CARTERSVILLE 70 89 71 94 / 60 40 30 10 COLUMBUS 72 92 73 96 / 60 40 30 10 GAINESVILLE 70 89 71 94 / 60 40 30 10 MACON 72 92 72 97 / 60 40 30 10 ROME 70 89 71 95 / 60 40 30 20 PEACHTREE CITY 71 89 71 94 / 60 40 30 10 VIDALIA 74 95 74 97 / 40 40 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
750 PM EDT MON AUG 18 2014 .PREV DISCUSSION... /ISSUED 320 PM EDT MON AUG 18 2014/ SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... STALLED FRONTAL BOUNDARY STRETCHES FROM THE TN VALLEY TO THE SOUTHERN MID ATLANTIC STATES. A HIGH PRESSURE RIDGE IS SITUATED ACROSS NORTHERN FL. 500MB ANALYSIS AND WV LOOP SHOWS A POTENT SHORTWAVE MOVING EAST ACROSS NORTHERN MS. THIS FEATURE WILL BE THE FOCUS FOR LATE AFTERNOON AND EVENING CONVECTION ACROSS THE CWFA. THE 16Z HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION THIS AFTERNOON. HAVE TRIED TO ORIENT THE POPS ACCORDING TO CURRENT RADAR TRENDS AND CLOSE TO THE HRRR SOLUTION. GOOD INSTABILITY DOES EXIST AT THE SURFACE...BUT LAPSE RATES REMAIN POOR UNTIL THE COLD POOL ALOFT MOVES OVERHEAD. BY THE TIME THE SHORTWAVE NEARS THE CWFA...INSTABILITY HAS DECREASED WITH THE LOSS OF HEATING. HOWEVER...WITH UNIDIRECTIONAL FLOW...STORMS MAY MOVE REPEATEDLY OVER THE SAME AREAS...WITH LOCALLY HEAVY RAINFALL POSSIBLE. AREAS TO THE NORTH RECEIVED ONE TO TWO INCHES OF RAINFALL OVERNIGHT/EARLY THIS MORNING...SO ANY TRAINING STORMS OR HEAVY RAINFALL MAY CAUSE SOME LOCALIZED FLOODING. BY EARLY TUESDAY...THE POTENT EVENING/OVERNIGHT SHORTWAVE WILL HAVE MOVED OFF TO THE EAST. MODELS ARE PROGGING ANOTHER...WEAKER... SHORTWAVE TO MOVE EAST IN THE FLOW TOMORROW. CONFIDENCE IS LOW ON EXACTLY WHERE CONVECTION WILL DEVELOP TOMORROW. NLISTEMAA LONG TERM /WEDNESDAY THROUGH MONDAY/... LONG TERM FORECAST IS ON TRACK AND HAVE NOT MADE SIGNIFICANT ADJUSTMENTS. ONE ADDITIONAL POINT TO NOTE IS THAT HEAT INDEX VALUES ARE CREEPING ABOVE 100 DEGREES SOUTH OF AN ATLANTA TO ATHENS LINE...WITH PORTIONS OF CENTRAL GEORGIA APPROACHING 105 DEGREES DURING THE SECOND HALF OF THE WEEK. IF THIS TREND CONTINUES...MAY NEED A HEAT ADVISORY FOR THESE 105-108 DEGREE VALUES ACROSS THE SOUTHEAST PART OF THE CWA. 11/ATWELL LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... 00Z GFS AND ECMWF ARE IN UNCOMMONLY GOOD AGREEMENT THROUGH THE EXTENDED FORECAST PERIOD AND CONTINUE THE RECENT TREND OF BUILDING UPPER-LEVEL HIGH PRESSURE INTO THE CENTRAL GULF COAST REGION AND LOWER MISSISSIPPI VALLEY FROM MID-WEEK THROUGH NEXT WEEKEND. BY THE WEEKEND THE UPPER RIDGE IS QUITE STRONG...BUT GEORGIA REMAINS ON THE EASTERN PERIPHERY. THIS SHOULD ALLOW VERY WARM TEMPERATURES AND INHIBIT DIURNAL CONVECTION SOMEWHAT...BUT I DO NOT BELIEVE THE FORECAST AREA IS CLOSE ENOUGH TO THE CENTER OF THE RIDGE TO ELIMINATE POPS ALTOGETHER. 20 && .AVIATION... 00Z UPDATE... AREA OF TSRA AFFECTING MOST TAF SITES THIS EVENING...THOUGH SHOULD SEE A DIMINISHING TREND OVER THE NEXT FEW HOURS. EXPECT TO SEE MVFR CIGS DEVELOP OVERNIGHT AND CANNOT RULE OUT BRIEF IFR CIGS. CLEARING TOMORROW MORNING BUT HAVE INCLUDED PROB30 DURING THE AFTERNOON TO COVER CHANCE OF CONVECTION. WINDS W THROUGH THE PERIOD GENERALLY BETWEEN 5-10KT THOUGH VRB AND GUSTY IN TSRA THIS EVENING...AND LOW END GUSTS TUESDAY. //ATL CONFIDENCE...00Z UPDATE... HIGH ON CONVECTION TONIGHT...MEDIUM ON TIMING OF CLEARING. MEDIUM ON EARLY MORNING CIGS...LOW ON POTENTIAL IFR DEVELOPMENT. HIGH ON ALL OTHER ELEMENTS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 91 72 97 / 50 40 30 10 ATLANTA 72 88 73 94 / 60 40 30 10 BLAIRSVILLE 67 84 67 90 / 60 40 30 20 CARTERSVILLE 70 89 71 94 / 60 40 30 10 COLUMBUS 74 92 73 96 / 60 40 30 10 GAINESVILLE 71 89 71 94 / 60 40 30 10 MACON 73 92 72 97 / 60 40 30 10 ROME 71 89 71 95 / 60 40 30 20 PEACHTREE CITY 71 89 71 94 / 60 40 30 10 VIDALIA 75 95 74 97 / 40 40 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
353 AM EDT SUN AUG 17 2014 .SYNOPSIS... HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF COAST WILL DOMINATE INTO MONDAY. THIS WILL RESULT DRY CONDITIONS WITH SEASONABLE TEMPERATURES TODAY. A PASSING UPPER DISTURBANCE AND INCREASING MOISTURE WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS ON MONDAY...FOLLOWED BY WARMING TEMPERATURES THROUGH MID WEEK AS AN UPPER RIDGE BUILDS OVER THE REGION. && .NEAR TERM /THROUGH TONIGHT/... ZONAL WESTERLY MID LEVEL FLOW IS EXPECTED TO PERSIST TODAY ACROSS THE CAROLINAS WHILE AN UPPER TROUGH SLIDES ACROSS NEW ENGLAND AND OFF THE NORTHEAST COAST BY TONIGHT. AT THE SURFACE...WEAK HIGH PRESSURE CONTINUES TO RIDGE INTO THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. SOUTHWESTERLY SURFACE WINDS WILL ENSURE WEAK MOIST WARM ADVECTION. FORECAST SOUNDINGS INDICATE LOWERING PRECIPITABLE WATER VALUES TO BELOW 1.5 INCHES (BELOW 1.25 INCHES ON THE NAM) AND SHOW A CAPPING INVERSION JUST BELOW 700MB...WHICH SHOULD PREVENT DIURNAL CONVECTION THIS AFTERNOON AND EVENING. HIGH TEMPERATURES TODAY WILL BE SLIGHTLY WARMER THAN YESTERDAY IN THE MID 90S WITH HEAT INDICES AROUND 100 DEGREES UNDER MOSTLY SUNNY SKIES. OVERNIGHT LOWS TONIGHT WILL FALL INTO THE LOWER 70S UNDER AVERAGE RADIATIONAL COOLING CONDITIONS AS SOME MID LEVEL CLOUDS MAY MOVE INTO THE ARE FROM THE WEST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... CHANCES OF RAIN RETURN TO THE FORECAST AREA ON MONDAY AS SHORTWAVE ENERGY MOVES ACROSS THE CENTRAL APPALACHIANS AND PVA COINCIDES WITH MODERATE DIURNAL INSTABILITY WITH INCREASING ATMOSPHERIC MOISTURE AS PWAT VALUES RISE TO OVER 1.75 INCHES. INCREASED POPS TO HIGHER CHANCE ACROSS THE NORTHERN MIDLANDS CLOSER TO THE UPPER SUPPORT WHILE MAINTAINING CHANCE POPS ELSEWHERE MONDAY AFTERNOON INTO EARLY EVENING. TEMPERATURES WILL AGAIN BE WARM BUT MAY BE TEMPERED A BIT BY INCREASED CLOUDINESS WITH HIGHS IN THE LOWER TO MID 90S. ANY LINGERING CONVECTION SHOULD DIMINISH BY MIDNIGHT TO 2AM AS SHORTWAVE ENERGY SHIFTS EAST OF THE FORECAST AREA. OVERNIGHT LOWS MONDAY NIGHT WILL BE IMPACTED BY LINGERING CLOUD COVER AND TEMPERATURES EXPECTED TO BE IN THE LOWER TO MID 70S. GENERALLY ZONAL WEST-NORTHWESTERLY MID LEVEL FLOW AGAIN SETS UP ACROSS THE CAROLINAS FOR TUESDAY PROVIDING A WEAK DOWNSLOPING COMPONENT TO THE LOW LEVEL FLOW. EXPECT MAINLY DIURNAL CONVECTION WITH THE BEST CHANCES IN THE EASTERN MIDLANDS WHERE LINGERING MOISTURE WILL BE BETTER AND THERE IS THE POSSIBILITY OF SEA BREEZE INTERACTION. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE NORMAL IN THE LOWER TO MID 90S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... SOME UNCERTAINTY IN THE EXTENDED PERIODS...ESPECIALLY BY NEXT WEEKEND. GENERALLY ZONAL WESTERLY FLOW WILL BECOME MORE AMPLIFIED LATE IN THE WEEK WITH DEEP TROUGHING IN THE WESTERN UNITED STATES RESULTING IN DOWNSTREAM RIDGING OVER THE MISSISSIPPI AND TENNESSEE VALLEY...WHILE ANOTHER TROUGH DIVES SOUTH ACROSS NEW ENGLAND INTO THE MID-ATLANTIC. WILL MAINTAIN THE DIURNAL POPS FOR CONVECTION WHILE TEMPERATURES ARE EXPECTED TO WARM BACK ABOVE NORMAL DURING THIS PERIOD. MEDIUM RANGE MODELS TRENDING TOWARDS A BACK DOOR FRONT NEXT SATURDAY BUT THE GFS IS MUCH MORE AMPLIFIED AND AGGRESSIVE WITH THE BACKDOOR FRONT COMPARED TO THE ECMWF...AND THEREFORE LOW CONFIDENCE AT THIS TIME. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD...ONLY EXCEPTION WILL BE OVERNIGHT INTO THE EARLY MORNING HOURS. ALREADY HAVE SOME FOG THAT HAS DEVELOPED AT AGS AND EXPECT CONDITIONS THERE TO DETERIORATE FROM TIME TO TIME. EXPECT MAINLY IFR/LIFR THROUGH 13Z...THEN IMPROVING CONDITIONS. THERE IS A VERY WEAK PRESSURE GRADIENT ACROSS THE AREA AND WINDS OVERNIGHT WILL BE CALM/LIGHT AND VARIABLE. NOCTURNAL COOLING AND LINGERING LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY MORNING. SOME DRYING WILL OCCUR IN THE WEST-SOUTHWEST LOW-LEVEL FLOW. HRRR INDICATES SOME FOG AND ESPECIALLY STRATUS DEVELOPING THROUGH THE EARLY MORNING HOURS ALONG THE SAVANNAH RIVER VALLEY. HAVE ALSO INCLUDED A TEMPO GROUP FOR SOME MVFR CONDITIONS AT OGB/CAE/CUB BUT NOT DNL THROUGH 13Z. DURING THE DAY...EXPECT VFR CONDITIONS WITH WINDS BECOMING SW TO W THROUGH THE AFTERNOON AND RANGING FROM 5 TO 8 KNOTS. THE ATMOSPHERE LOOKS TO BE CAPPED AND IF ANY CONVECTION DEVELOPS EXPECT IT TO BE ISOLATED. EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING FOG THROUGH THE PERIOD. A SLIGHTLY BETTER CHANCE OF SCATTERED AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
142 AM EDT SUN AUG 17 2014 .SYNOPSIS... HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW- LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE MODELS INDICATE DRYING WITH THE WESTERLY COMPONENT TO THE LOW- LEVEL FLOW SO FOG WILL LIKELY NOT BE AS EXTENSIVE AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... A DRY FORECAST IS ON TAP THROUGH SUNDAY AND SUNDAY NIGHT WITH TEMPERATURES SUNDAY AFTERNOON A LITTLE ABOVE NORMAL IN THE MID 90S. && .LONG TERM /MONDAY THROUGH SATURDAY/... ZONAL UPPER LEVEL FLOW ON MONDAY SLOWLY EVOLVES INTO NW FLOW ALOFT BY THE END OF THE WEEK AS A RIDGE OF HIGH PRESSURE BUILDS JUST TO OUR WEST. LOW LEVEL MOISTURE FLUX IS FROM THE WEST TO NORTHWEST THROUGH THE PERIOD SO NOT A LOT OF MOISTURE TO SUPPORT PRECIPITATION. MODELS INDICATE AN UPPER WAVE MOVING EAST OVER THE AREA MONDAY AFTERNOON INTO TUESDAY WHICH MAY BE A FORCING MECHANISM FOR CONVECTION. POPS ARE GENERALLY 10 TO 20 PERCENT AT NIGHT AND 20 TO 30 PERCENT DURING THE DAY. TEMPS ABOVE NORMAL WITH BUILDING RIDGE AND INSTABILITY MAY SUPPORT WIDELY SCATTERED MAINLY DIURNAL CONVECTION. GFS SHOWS BACK DOOR FRONT NEXT SATURDAY BUT THAT IS STILL A WAYS OFF. && .AVIATION /06Z SUNDAY THROUGH FRIDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD...ONLY EXCEPTION WILL BE OVERNIGHT INTO THE EARLY MORNING HOURS. ALREADY HAVE SOME FOG THAT HAS DEVELOPED AT AGS AND EXPECT CONDITIONS THERE TO DETERIORATE FROM TIME TO TIME. EXPECT MAINLY IFR/LIFR THROUGH 13Z...THEN IMPROVING CONDITIONS. THERE IS A VERY WEAK PRESSURE GRADIENT ACROSS THE AREA AND WINDS OVERNIGHT WILL BE CALM/LIGHT AND VARIABLE. NOCTURNAL COOLING AND LINGERING LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY MORNING. SOME DRYING WILL OCCUR IN THE WEST-SOUTHWEST LOW-LEVEL FLOW. HRRR INDICATES SOME FOG AND ESPECIALLY STRATUS DEVELOPING THROUGH THE EARLY MORNING HOURS ALONG THE SAVANNAH RIVER VALLEY. HAVE ALSO INCLUDED A TEMPO GROUP FOR SOME MVFR CONDITIONS AT OGB/CAE/CUB BUT NOT DNL THROUGH 13Z. DURING THE DAY...EXPECT VFR CONDITIONS WITH WINDS BECOMING SW TO W THROUGH THE AFTERNOON AND RANGING FROM 5 TO 8 KNOTS. THE ATMOSPHERE LOOKS TO BE CAPPED AND IF ANY CONVECTION DEVELOPS EXPECT IT TO BE ISOLATED. EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING FOG THROUGH THE PERIOD. A SLIGHTLY BETTER CHANCE OF SCATTERED AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
542 PM MDT MON AUG 18 2014 .UPDATE... UPDATED EVENING FORECAST TO MENTION ISOLATED TO SCATTERED THUNDERSTORMS ACROSS THE UPPER SNAKE PLAIN BASED UPON RADAR TRENDS. MUCH OF THE ACTIVITY SHOULD DIMINISH AFTER SUNSET. VALLE && .PREV DISCUSSION... /ISSUED 144 PM MDT MON AUG 18 2014/ DISCUSSION...CENTER OF UPPER LOW OVER NORTHERN CALIFORNIA PER WV IMAGERY. MOISTURE PULLING NORTH THROUGH NEVADA AND NORTHERN ARIZONA THROUGH GREAT BASIN TOWARD EASTERN IDAHO. PAIR OF WEAK SHORTWAVES MOVING THROUGH EAST IDAHO...ONE ALONG DIVIDE AND ANOTHER ALONG SOUTHERN BORDER. SOME MOISTURE IN PLACE ALREADY AND CONVECTION HAS BEGUN TO REDEVELOP ALREADY EARLY THIS AFTERNOON ALONG/AHEAD OF SHORTWAVES. NAM/RAP SEEMS TO HAVE BEST HANDLE ON CONVECTIVE THREAT THIS AFTERNOON AND EVENING WHILE HRRR STRUGGLING TO CATCH UP. BOTH NAM/GFS CONTINUE CONVECTION OVERNIGHT INTO EARLY TUESDAY BUT CONVECTION BLOOMS DURING THE AFTERNOON AS MID LEVEL MONSOON FLOW REACHES EAST IDAHO. HAVE NUDGED POPS UPWARD TUESDAY ALL AREAS. SOME DIFFERENCES IN MODELS AS NAM STRONGER WITH SHORTWAVE EJECTING OUT OF EAST IDAHO TUESDAY NIGHT. DIFFERENCES AMPLIFY THROUGH THURSDAY WITH NAM A BIT FURTHER SOUTH WITH BASE OF TROUGH. GFS HOLDS EAST IDAHO IN NEUTRAL FLOW ALOFT WITH SOUTHERN CUT OFF LOW FURTHER NORTH THAN THE NAM. BOTH MODELS REMAIN UNSETTLED WITH PLENTY OF MOISTURE IN PLACE TO CONTINUE THREAT OF SCATTERED THUNDERSTORMS ACROSS THE REGION. SHORTWAVE ROUNDS TROUGH WEDNESDAY NIGHT INTO THURSDAY FOR ANOTHER WET DAY MOST AREAS WITH EASTERN IDAHO JUST AHEAD OF MAIN TROUGH AXIS. BOTH MODELS PRODUCING MORE WIDESPREAD CONVECTIVE COVERAGE SO NUDGED POPS UPWARD AGAIN FOR THURSDAY AFTERNOON/EVENING. ECMWF AND GFS AGAIN DIFFERING IN DETAILS FOR REMAINDER OF FORECAST. ECMWF LOOKING AGAIN TO DROP CLOSED SHORTWAVE INTO BASE OF BROAD PACNW TROUGH THURSDAY NIGHT INTO FRIDAY BUT THEN OPENS IT UP AGAIN FRIDAY NIGHT. PLACEMENT/DEPTH OF TROUGH SIMILAR WITH HINTS OF DRY SLOT WORKING IN FROM OREGON FRIDAY INTO SATURDAY. BOTH MODELS TREAT NORTHERN PACIFIC ENERGY A LITTLE DIFFERENTLY. EAST IDAHO UNDER SOME INFLUENCE OF BASE OF TROUGH...BUT FLOW RANGES FROM WEST/DRY IN THE GFS TO NORTHWEST/MOIST IN THE ECMWF. OVERALL OPTED TO MAKE NO CHANGES TO CURRENT EXTENDED RANGE WITH ISOLATED POPS CLOSE TO CLIMO AND TEMPS NEAR GUIDANCE BLEND. DMH AVIATION...SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH TOMORROW ACROSS EASTERN IDAHO. COVERAGE WILL BE ISOLATED TODAY BECOMING CLOSER TO SCATTERED IN SOME AREAS ON TUESDAY. GUSTY WINDS OVER 30KTS ARE POSSIBLE WITH STORMS...WITH AN INCREASING THREAT OF HEAVY DOWNPOURS TONIGHT AND TUESDAY. EITHER COULD BRING REDUCED VISIBILITY. WE WILL BE CARRYING AT LEAST VCTS OR VCSH FOR ALL SITES. KEYES FIRE WEATHER...SHOWERS AND STORMS WILL CONTINUE TO INCREASE ACROSS EASTERN IDAHO THROUGH THE NEXT 24 HOURS. THUNDERSTORM COVERAGE WILL BE ISOLATED TODAY AND WIDELY SCATTERED TOMORROW. THE SOUTHEAST CORNER WILL BE INTERESTING TO WATCH AS THEY MAY BE TOO STABLE TO SEE ANY THUNDER AT ALL IF CLOUDS AND TIMING MATCH UP. STORMS WILL BE CAPABLE OF PRODUCING WIND GUSTS OVER 35 MPH AND LOCALLY HEAVY DOWNPOURS. WE ARE NOT EXPECTING ANY ISSUES WITH SLIDES OR FLOODING THIS TIME AROUND. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE THROUGH THE END OF THE WEEK AS THE LOW OUT OF CANADA SAGS SOUTH INTO THE NORTHERN STATES. THE BETTER CHANCES WEDNESDAY-FRIDAY WILL BE ACROSS THE NORTH AND ALONG THE WYOMING BORDER. DRIER CONDITIONS WILL FILTER INTO PORTIONS OF THE SNAKE PLAIN AND SOUTH-CENTRAL HIGHLANDS...HELPING TO REDUCE SHOWERS/STORMS. WE WILL ALSO SEE THE WIND PICKING UP...BUT INCREASED HUMIDITY SHOULD NEGATE THIS AND PREVENT ANY ISSUES WITH CRITICAL FIRE CONDITIONS. THE MODELS CONTINUE TO SHOW WIDELY VARYING FORECASTS EACH DAY IN THE EXTENDED...BUT ONE TREND IS EMERGING DESPITE ALL OF THIS. IT DOES APPEAR FOR THE WEEKEND AND EARLY NEXT WEEK...WE SHOULD BR PRETTY DRY BUT BREEZY ACROSS THE SOUTH AND SNAKE PLAIN. WE SLOWLY TRENDED THAT DIRECTION WITH THE FORECAST WHERE IT WAS NEEDED...BUT NOT COMPLETELY TO THAT END OF THE SPECTRUM. KEYES && .PIH WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
959 PM CDT MON AUG 18 2014 .DISCUSSION... 650 PM...EARLY EVENING UPDATE...CONVECTION FIRING ACROSS CENTRAL WI WILL CONTINUE THIS EVENING WITH ADDITIONAL THUNDERSTORMS RAPIDLY DEVELOPING OVER FAR NORTHERN IA AND SOUTHERN MN. THIS ACTIVITY WILL SLOWLY SAG SOUTH BUT PROBABLY NOT REACH NORTHERN IL UNTIL AFTER 04Z-05Z. ACTIVITY WILL THEN SPREAD SOUTHEAST ACROSS MAINLY THE NORTHERN TWO THIRDS OF THE CWA OVERNIGHT. SHORT TERM/ HI RES GUIDANCE IS IN FAIR AGREEMENT WITH MUCH OF THE AREA NOW STAYING DRY THROUGH MIDNIGHT. HAVE UPDATED GRIDS/ZFP FOR THESE TRENDS ALONG WITH MOSTLY CLEAR SKIES OVER MUCH OF THE AREA AS CU FIELD DISSIPATES...THOUGH HIGH CLOUDS WILL LIKELY QUICKLY SPREAD ACROSS THE AREA LATER THIS EVENING AS STORMS APPROACH. NO CHANGES TO LIKELY POPS OVERNIGHT THOUGH POPS MAY NEED TO BE LOWERED ACROSS THE FAR SOUTH AS TRENDS EMERGE. CMS //PREV DISCUSSION... 239 PM CDT SYNOPSIS...A WARMER AND NOTICEABLY MORE HUMID PATTERN WILL BE DEVELOPING THROUGH MID WEEK. IN ADDITION TO THE WARMTH AN EVOLVING UPPER AIR PATTERN WILL BRING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND. HIGH TEMPERATURES LATER IN THE WEEK MAY BE DICTATED BY THE CONVECTION. TONIGHT... A LOW PRESSURE TROUGH IS OVER MINNESOTA AND IT WILL BECOME A CLOSED LOW OVER WISCONSIN AND LAKE SUPERIOR TUESDAY EVENING. AT THE SURFACE THERE IS A LOW PRESSURE TROUGH OVER MINNESOTA THAT WILL BECOME A CLOSED LOW OVER WISCONSIN TOMORROW MORNING. THE LOW WILL PUSH EAST OF THE LAKE WEDNESDAY. EXPECTING THE FIRST ROUND OF STORMS TO MOVE INTO THE RFD AREA THIS EVENING WITH THE MAJORITY OF CONVECTIVE ACTIVITY REMAINING OVER WISCONSIN CLOSER TO THE LOW. THE FIRST WAVE WILL WEAKEN AS IT PUSHES EAST. A SECOND WAVE FORMS AHEAD OF A VORT STREAMER OVERNIGHT AND THINKING THIS WILL BE THE MAIN SHOW TONIGHT. EXPECTING ACTIVITY TO REMAIN NORTH OF I-80 MOST OF THE NIGHT. ACTIVITY WILL THEN SPREAD SOUTH AND EAST COVERING AREAS EAST OF I-39 EARLY TUESDAY MORNING. THIS ACTIVITY WILL WEAKEN THROUGH THE MORNING AND CONTINUE SOUTHEAST OUT OF THE WARNING AREA. THE FIRST CONCERN OVERNIGHT IS HEAVY RAIN AS PWAT VALUES WILL BE BETWEEN 1.5 AND 1.75 INCHES. CAPE VALUES WILL BE AROUND 1000 J/KG THIS EVENING AND THEN DIMINISH OVERNIGHT. SHEAR VALUES ARE 20-30 KT SO SEVERE WEATHER IS NOT EXPECTED...BUT SMALL HAIL MAY OCCUR WITH THE STRONGEST STORMS. STEERING LEVEL FLOW IS ALSO WEAK SO STORMS WILL BE SLOW MOVING WHICH COULD ENHANCE RAINFALL TOTALS. THE OTHER CONCERN IS FOG TONIGHT. IF WE CLEAR OUT AT ALL EXPECTING AREAS OF DENSE FOG TO DEVELOP. HAVE MEDIUM CONFIDENCE IN SKY COVER SO ONLY HAVE PATCHY FOG IN THE FORECAST TONIGHT AFTER MIDNIGHT. TUESDAY AND TUESDAY NIGHT... MORE STORMS ARE EXPECTED AS THE LOW SHIFTS EAST OVER WISCONSIN. EXPECTING FOG/LOW STRATUS/GENERAL CLOUD COVER TO THIN TUESDAY MORNING. HEATING WILL RESULT IN DECENT CAPE VALUES. THE MOISTURE RICH NAM FEATURES THE HIGHEST CAPE VALUES AROUND 3000 J/KG BUT THE MORE CONSERVATIVE GFS ONLY SHOWS LESS THAN 1000 J/KG. SHEAR VALUES STILL LOOK MARGINAL AROUND 35 KT. BUT PWAT VALUES WILL BE A BIT LOWER AT 1.3 TO 1.5 INCHES. HEAVY RAIN IS STILL POSSIBLE BUT STORMS SHOULD BE MOVING AT A BETTER PACE WITH STRONGER STEERING LEVEL FLOW. THE FORCING WILL BE A COMBO OF THE LOWS FRONT THAT MOVES THROUGH IN THE LATE AFTN/EVENING AND VORTICITY STREAMERS THAT ROTATE AROUND THE LOW. HAVE MEDIUM CONFIDENCE IN WIDESPREAD TS COVERAGE...BUT KEPT POPS IN THE CHANCE RANGE DUE TO LOW CONFIDENCE IN WHEN AND WHERE STORMS WILL DEVELOP. HAIL AND STRONG WINDS ARE POSSIBLE IN ADDITION TO THE HEAVY DOWNPOURS. TEMPS REMAIN A CHALLENGE AS WE COULD BE WARMER IF SKY COVER IS ON THE WEAKER SIDE. HOWEVER...HAVE MEDIUM CONFIDENCE IN WIDESPREAD TS COVERAGE SO KEPT HIGH TEMPS IN THE LOW TO MID 80S. JEE WEDNESDAY THROUGH SUNDAY... THE UPPER LOW OVER THE UPPER GREAT LAKES WILL START TO MOVE MORE QUICKLY TO THE NORTHEAST WEDNESDAY MORNING AS NORTHERN PACIFIC TROUGHING PUSHES INLAND OVER WESTERN CANADA. THIS HELPS TO PUSH CUTOFF LOW PRESSURE ONTO THE CALIFORNIA COAST WITH BOTH OF THESE FEATURES HELPING TO DRIVE UPPER RIDGE DEVELOPMENT OVER THE HIGH PLAINS. THE LOCAL AREA WILL BE BETWEEN THE DEPARTING UPPER LOW AND THE APPROACHING RIDGE WEDNESDAY MORNING WITH WEAK LOW LEVEL FLOW IN PLACE AS WELL. THIS SHOULD RESULT IN DRY WEATHER FOR MUCH OF WEDNESDAY BEFORE MID LEVEL BAROCLINICITY INCREASES LATE IN THE DAY AND MORE SO IN THE EVENING AS THE RIDGE APPROACHES. PRECIPITABLE WATER VALUES WILL INCREASE MARKEDLY WITH THE ARRIVAL OF THE MID LEVEL WARM ADVECTION LEADING TO MOIST ASCENT WEDNESDAY EVENING AND WEDNESDAY NIGHT. THIS LIFT ALONE MAY BE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS AND MAY BE AIDED BY THE PASSAGE OF AN UPPER WAVE WHICH GUIDANCE HAS BEEN HINTING AT. THIS IS CERTAINLY PLAUSIBLE GIVEN THE PRESENCE OF THE DEEP TROUGH TO THE WEST AND THE TENDENCY FOR WAVES TO EMANATE FROM IT. WILL CARRY HIGHEST POPS LATE WEDNESDAY EVENING THROUGH THURSDAY MORNING. THE RIDGE AXIS WILL SHIFT EASTWARD ACROSS THE AREA THROUGH FRIDAY. THE AMPLITUDE OF THE RIDGE AND THEREFORE THE POSITIONING OF THE TRACK OF SHORTWAVES/THUNDERSTORMS ALONG ITS NORTHERN PERIPHERY WILL BE DRIVEN BY THE SPEED WITH WHICH THE LARGE WESTERN UPPER TROUGH EVOLVES EASTWARD. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE TROUGH AND THEREFORE SHARPER WITH THE RIDGE SUGGESTING THAT THE MAIN STORM TRACK WILL BE NORTH OF THE LOCAL AREA FRIDAY WHEREAS THE SLOWER AND LOWER AMPLITUDE ECMWF KEEPS THE FAVORED TRACK ACROSS THE AREA INTO THE WEEKEND. THE UPPER TROUGH WILL EVOLVE EASTWARD PUSHING THE RIDGE TO THE EAST AND BRINGING A COOL FRONT INTO THE REGION LATE IN THE WEEKEND. THE BIGGEST UNCERTAINTY IS THE TIMING. WITH PRECIPITABLE WATER VALUES OVER 2 INCHES FROM THURSDAY ONWARD HEAVY RAINFALL WILL BE A CONCERN WITH ANY STORMS...ESPECIALLY IF MULTIPLE ROUNDS ARE ABLE TO AFFECT THE AREA THROUGH THE WEEKEND. HOWEVER A SHARPER RIDGE WOULD RESULT IN A SHIFT IN THE TRACK TO THE NORTH AND STRONGER CAPPING LOCALLY. TEMPERATURES WILL BE WARMING INTO THE MID 80S WEDNESDAY AND MOSTLY MID AND UPPER 80S FROM THURSDAY INTO THE WEEKEND. LAKESHORE AREAS WILL LIKELY BE COOLER MOST DAYS WITH LAKE INFLUENCES EXPECTED DUE TO A RATHER LIGHT LOW LEVEL FLOW. THUNDERSTORMS AND ANY REMNANT INFLUENCES MAY NEGATIVELY AFFECT HIGHS DEPENDING ON THEIR TIMING. CANNOT RULE OUT SOME 90 DEGREE READINGS IN THE WEST AND SOUTH LATE IN THE WEEK...ESPECIALLY IF THUNDERSTORM ACTIVITY KEEPS AT A MINIMUM. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * A PERIOD OF SHRA/TSRA LIKELY SOMETIME BETWEEN 08Z-11Z. * POTENTIAL FOR LOWER CIGS LATE TONIGHT INTO TUE MORNING. * CHANCE FOR SCATTERED SHRA/TSRA MUCH OF TUE WITH A SLIGHTLY MORE FAVORED TIME DURING THE AFTERNOON. //DISCUSSION...UPDATED 00Z... A QUIET EVENING IS EXPECTED OVER LOCAL AIRPORTS BEFORE TSRA CHANCES INCREASE OVERNIGHT. MUCH OF THE CUMULUS IS EXPECTED TO FADE WITH SOUTH TO SOUTHWEST WINDS. REGENERATING STORMS ACROSS CENTRAL WISCONSIN WILL LIKELY EVOLVE SLOWLY SOUTHEAST...HOWEVER THESE ARE NOT ANTICIPATED TO REACH ALL THE WAY DOWN INTO NORTHERN IL. EVEN IF THEY WERE TO BY LATE THIS EVENING...THEY SHOULD SLOWLY FADE IN INTENSITY. AN UPPER LEVEL DISTURBANCE OVER MN WILL ROTATE ITS WAY EAST- SOUTHEAST WITH THE SOUTHERN AREA OF FORCING MOVING OVER NORTHERN IL AND NORTHWEST IN LATE TONIGHT. COMPLIMENTING THIS WILL BE A MOIST LOW-LEVEL AIR MASS THAT WILL FURTHER BE MOISTENING OVERNIGHT AND COULD BLOSSOM MVFR CIGS OVERNIGHT. STORMS ARE EXPECTED TO BE SCATTERED TO NUMEROUS IN COVERAGE AS THEY PROGRESS EASTWARD OVER THE AREA. BY DAYBREAK WHAT IS LEFT OF THESE SHOULD BE MAINLY EAST OF THE TERMINALS...HOWEVER REDEVELOPING SHOWERS AND POSSIBILITY A FEW STORMS COULD OCCUR TUESDAY MORNING. AS THE SYSTEM COLD FRONT MOVES THROUGH DURING THE AFTERNOON...SCATTERED REDEVELOPMENT OF STORMS IS PROBABLE...BUT PLACEMENT OF THAT IS DIFFICULT TO TELL AT THIS POINT. SOUTHWEST WINDS WILL TURN WESTERLY WITH THIS FRONTAL PASSAGE WITH SOME GUSTS POSSIBLE BOTH AHEAD AND BEHIND THE FRONT. //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM IN SHRA AND/OR TSRA OCCURRING LATE TONIGHT BUT LOW IN SPECIFIC DURATION. * HIGH IN WIND DIRECTION AND MEDIUM IN WIND SPEED THROUGH MUCH OF THE TAF. THE EXCEPTION WOULD BE DURING AND IMMEDIATELY AFTER ANY STORMS...BUT ANY SHIFT FROM SOUTH-SOUTHWEST SHOULD BE TEMPORARY. * LOW IN MVFR CIGS OCCURRING LATE TONIGHT INTO TUE MORNING. * LOW IN WHETHER TSRA OCCURS TUESDAY AND IN SPECIFIC TIMING. //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...CHANCE OF TSRA AND LOWER CIGS DURING THE NIGHT. THURSDAY-SATURDAY...PERIODS OF TSRA POSSIBLE. SUNDAY...SLIGHT CHANCE OF TSRA. MTF && .MARINE... 239 PM CDT LOW PRESSURE OVER MINNESOTA WILL MOVE OVER WISCONSIN TOMORROW AND THEN OVER THE LAKE TOMORROW EVENING AND NIGHT. WINDS WILL BECOME SOUTH ACROSS THE LAKE AND INCREASE TO 15 TO 25 KT OVERNIGHT. AS THE LOW MOVES OVER THE LAKE TOMORROW...WINDS WILL DIMINISH SLOWLY OVER THE SOUTH HALF AND BECOME SW. ON THE NORTH HALF...WINDS WILL ALSO DIMINISH AND BECOME SE TO E AHEAD OF THE LOW. THE LOW SHIFTS EAST OF THE LAKE TUESDAY NIGHT AND WINDS BECOME NW 10-15 KT. THE LOW SHIFTING TO THE EAST WILL LEAVE A WEAK PRESSURE GRADIENT IN ITS WAKE. THIS WILL RESULT IN LIGHT ONSHORE OR VARIABLE WINDS WEDNESDAY WITH BEFORE A SOMEWHAT BETTER ORGANIZED PRESSURE GRADIENT SPREADS IN WITH LOW PRESSURE FROM THE CENTRAL HIGH PLAINS TO NORTHERN MANITOBA. THIS WILL BRING MAINLY SOUTH TO SOUTHEAST WINDS ACROSS THE LAKE THURSDAY...WITH OCCASIONAL EAST WINDS OVER THE FAR NORTH...BUT EVEN THEN THE FLOW MAY BE WEAK ENOUGH TO SUPPORT A SHIFT TO ONSHORE WINDS THURSDAY AFTERNOON. SOUTH TO SOUTHEAST WINDS ARE FAVORED THROUGH THE WEEKEND BUT THERE MAY BE QUITE A BIT OF VARIABILITY IF THE LOW PRESSURE TO THE WEST EVOLVES MORE SLOWLY AS SOME FORECAST GUIDANCE INDICATES. THE UPPER FLOW PATTERN DOES LOOK TO SHIFT SUNDAY OR MONDAY BRINGING A COOL FRONT ACROSS THE LAKE WITH A SHIFT TO NORTHERLY WINDS WHICH MAY BE RATHER BREEZY. JEE/MDB && .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
  [top] Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 902 PM CDT Mon Aug 18 2014 .UPDATE... ISSUED AT 900 PM CDT MON AUG 18 2014 Skies have become mostly clear across central and SE Illinois this evening as diurnal heating ends. Although a few pockets of light fog are possible early tonight, the next main forecast feature will be the chance for thunderstorms overnight as an upper level shortwave and cold front move into central IL. Have trimmed back POPs before midnight as current radar and satellite indicate storms are still several hours away. HRRR model simulated reflectivity has been depicting movement of the system well in northern IA, southern MN, southwest WI this evening and has been used as a guide for timing through the first few hours of Tuesday. Currently the system is associated with a slight risk (15% +) of severe winds and hail to our northwest, but as it approaches central IL, CAPE of 3000 J/kg should be diminishing to around 1500 or less with marginal 0-6 km bulk shear around 25-30 kts. This is enough for only a 5% severe risk from the Illinois River northwest. To the south, risk of severe storms is negligible, but at least a slight chance for storms will reach as far as SE Illinois by early morning. Have sent updates for POP/Temp/Humidity/Wind trends this evening/early tonight. && .SHORT TERM...(This evening through Tuesday) ISSUED AT 311 PM CDT MON AUG 18 2014 Earlier stratus has given way to diurnal type clouds over central and southeast Illinois early this afternoon, underneath a weak high pressure axis. Leading edge of shortwave currently seen on water vapor imagery pushing through Minnesota and northern Iowa, with a more potent vorticity maximum moving out of North Dakota. Convection ahead of the shortwave expected to begin over the next couple hours over northern Iowa, where skies have been sunny and CAPE`s are over 3000 J/kg per SPC mesoanalysis. High-resolution models pushing the first wave of storms into Wisconsin with another line forming in southern Minnesota/northern Iowa later this evening. The second line is more of a concern for us as it will have a southeast trajectory. However, most of the models show some fading of the line with more of the energy staying to our north, and a separate convective cluster developing over northwest Missouri overnight. Have adjusted the PoP`s in our area to be primarily after midnight, and largely eliminated them south of I-70. Associated surface boundary expected to push into central Illinois Tuesday afternoon as the upper wave arrives. Some concerns with severe weather potential across east central and southeast Illinois, as development takes place early afternoon and bulk shear increases during the peak heating time. Latest Day2 SPC convective outlook indicates a severe threat southeast of a Danville to Effingham line, with NAM indicating a 2 pm to 7 pm time frame being the most concern. && .LONG TERM...(Tuesday night through Monday) ISSUED AT 311 PM CDT MON AUG 18 2014 Tuesday evening will see decreasing storm chances from north to south as a shortwave in the upper level trough over the Great Lakes advances east of IL. We are in the day 2 slight risk in our southeast counties, so we can`t rule out some lingering strong storms into early evening, but the main threat should advance southeast of IL by mid evening. Additional storm chances re-develop across our far S-SW counties late Tue night as a 300mb 75kt jet max in the back side of the trough generates some lift in the left exit region. Minor rain/storm chances will continue on Wednesday as the jet max progresses eastward over Illinois, but only slight chances are expected. Wednesday night, a warm front developing across our northern counties oriented from NW to SE will become a focus for a round of storms, with chances increasing to likely after midnight along and north of I-74. Storms should progress northward with the warm front on Thursday. However, storms chances are expected to linger north of a line from Peoria to Paris Thursday and Thursday night. Height rises and mid-level warming on Friday and Saturday should help to keep provide a capping layer, and reduce storm chances across central IL. The may be an isolated late afternoon or early evening flare-up of a storm, but most areas should stay dry. Rain-free conditions are forecast to continue into Sunday by the ECMWF and GFS. They both show a cold front arriving later Sunday night and wash-out as it passes across IL on Monday. The weakening front is not expected to trigger much in the way of storms at this point, but confidence is low on that scenario staying dry. Heat and humidity will definitely dominate the last half of this week, as highs climb into the upper 80s and lower 90s, with heat index readings in the mid to upper 90s. Some relief will come on Monday behind the cold front, with low to mid 80s for highs and lowering dewpoints into the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 659 PM CDT MON AUG 18 2014 Mainly VFR conditions across central/SE IL this evening as ceilings have lifted and scattered out. VFR conditions to continue until around 07-09Z when a line of thunderstorms moves into the region from the northwest. This line expected to weaken as it approaches and mainly affect TAF sites from KPIA and KBMI northward. Have included a PROB30 group at KPIA and KBMI to address potential MVFR visibilities with the storms moving through northern Illinois, but currently feel potential further south is still too uncertain to go more than the existing VCTS. A break in shower/thunderstorm activity likely in the morning then an upper level shortwave and daytime heating should produce a re-intensification of storms along the cold frontal boundary lingering over central Illinois and have brought VCTS and ceilings near MVFR thresholds for the remainder of the afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ONTON SHORT TERM...GEELHART LONG TERM...SHIMON AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 PM CDT SUN AUG 17 2014 .DISCUSSION... 301 PM CDT A WARMER...MORE HUMID...AND POTENTIALLY MORE UNSETTLED PATTERN IS ON THE WAY FOR MUCH OF THE UPCOMING WEEK. MOISTURE CHANNEL IMAGERY SHOWS THE UPPER LOW WHICH PROVIDED SOME SHOWER ACTIVITY YESTERDAY MOVING MORE STEADILY ACROSS THE OHIO VALLEY. TO THE NORTH...A WAVE IS MEANDERING EASTWARD ACROSS CENTRAL MINNESOTA WHILE A CLOSED UPPER LOW SPINS OVER SOUTHERN MANITOBA. THIS TROUGH WILL DETERMINE THUNDER CHANCES MONDAY NIGHT. ALSO OF NOTE IS A SERIES OF UPPER LOWS OVER THE NORTHERN PACIFIC NEAR ALASKA. ENERGY FROM THESE SYSTEMS WILL TRANSLATE INTO WESTERN/CENTRAL CANADA AND HELP FORCE UPPER RIDGING OVER THE U.S. MIDWEST BRINGING THE AFOREMENTIONED WARM UP. AT THE SURFACE...WEAK LOW PRESSURE IS OVER THE LOWER OHIO VALLEY IN CONJUNCTION WITH THE UPPER LOW. ANOTHER WEAK LOW IS STRETCHED ACROSS WESTERN MINNESOTA WHILE HIGH PRESSURE IS CENTERED OVER CENTRAL ONTARIO. ANOTHER LOW IS OVER SOUTHERN MANITOBA IN CONJUNCTION WITH THE BETTER ORGANIZED UPPER LOW IN THAT VICINITY. TONIGHT...THE MAIN CONCERN TONIGHT WILL BE FOG/STRATUS AS RESIDUAL LOW LEVEL MOISTURE LINGERS IN THE MIDST OF WEAK LOW LEVEL FLOW AND A WEAK RIDGE AXIS. THE RIDGE AXIS WILL STRETCH ACROSS NORTHWEST AND NORTH CENTRAL ILLINOIS BY MONDAY MORNING. WESTERN AREAS APPEAR TO BE FAVORED FOR FOG DEVELOPMENT WHILE EASTERN AREAS MAY SEE MORE IN THE WAY OF STRATUS...ESPECIALLY IF SOME EXISTING STRATUS IS UNABLE TO ERODE INTO THE EVENING...ESPECIALLY NEAR THE LAKE. WILL INCLUDE FOG MENTION IN THE FORECAST FOR MOST AREAS BUT THERE IS DECENT POTENTIAL FOR DENSE FOG SO WILL NEED TO MONITOR THIS. WESTERN AREAS LOOK TO HAVE THE BEST CHANCE FOR THIS AS THEY MAY CLEAR OUT THIS EVENING AND BE IN CLOSEST PROXIMITY TO THE RIDGE AXIS. MONDAY AND TUESDAY...THE UPPER WAVE OVER MINNESOTA WILL TRACK EAST WITH ITS EFFECTS LARGELY STAYING TO THE NORTH OF THE AREA INTO MONDAY MORNING...EXCEPT FOR SOME INCREASED MID AND HIGH LEVEL CLOUD COVER. HOWEVER THE MANITOBA LOW WILL BE TRACKING EAST-SOUTHEAST ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY MONDAY BEFORE SLOWING OVER THE WESTERN GREAT LAKES MONDAY NIGHT. THIS WILL PUSH ASCENT INTO THE AREA AS EARLY AS LATE MONDAY AFTERNOON IN THE NORTHWEST BUT MORE LIKELY MONDAY EVENING INTO MONDAY NIGHT. A MORE FOCUSED SURFACE TROUGH AXIS IS FORECAST TO CROSS THE AREA SOME TIME EARLY TUESDAY BRINGING THE MOST FOCUSED CHANCE FOR SHOWERS AND THUNDERSTORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN AREAS. LATEST FORECAST GUIDANCE SHOWS QUITE A BIT OF SPREAD IN TERMS OF TIMING OF THE BEST FOCUS FOR PRECIP. WILL CARRY HIGHEST POPS MONDAY EVENING AND OVERNIGHT WITH LOWER POPS LATER TUESDAY AS FOCUS IS LOST BUT UPPER CYCLONIC FLOW CONTINUES AROUND THE STALLED UPPER LOW TO THE NORTH FOR THE MORNING. SOME MODEST WARMING WILL OCCUR ALOFT MONDAY BUT PERIODIC BOUTS OF MID CLOUD MAY HELP LIMIT TEMPS SOMEWHAT...NOT TO MENTION IMPACT OF ANY MORNING STRATUS/FOG. FLOW WILL CONTINUE OFF THE LAKE KEEPING LAKESHORE AREAS COOLEST. WILL CARRY HIGHS IN THE LOW TO MID 70S LAKESIDE AND AROUND 80 INLAND MONDAY WITH SOUTH TO SOUTHWEST WINDS TUESDAY ALLOWING TEMPS TO REACH THE LOWER 80S FOR MOST PLACES UNLESS PRECIP TIMING SLOWS AND LINGERS THROUGH MORE OF THE DAY. WEDNESDAY INTO THE WEEKEND...A LARGER UPPER TROUGH WILL AMPLIFY OVER WESTERN CANADA INTO WEDNESDAY AS ANOTHER UPPER LOW DROPS SOUTHWARD DOWN THE CALIFORNIA COAST AND CUTS OFF. THIS WILL LEAD TO AMPLIFICATION OF AN UPPER RIDGE ACROSS THE HIGH PLAINS TUESDAY WHICH WILL QUICKLY SHIFT EAST INTO THE CENTRAL U.S. WEDNESDAY. THIS WILL BRING A PUSH OF WARM ADVECTION ACROSS THE AREA WEDNESDAY WHICH MAY BE ENOUGH TO KICK OFF SOME SHOWERS AND STORMS. WITH THE COMPLEX TROUGH PATTERN TO THE WEST THERE WILL BE THE TENDENCY FOR SHORTWAVES TO TRAVERSE THE RIDGE WITH SOME POTENTIAL FOR THIS TO BEGIN WEDNESDAY BUT IT APPEARS MORE LIKELY TO BEGIN WEDNESDAY NIGHT. THE RIDGE WILL PARK ITSELF OVER THE MIDWEST/WESTERN LAKES INTO FRIDAY KEEPING THE LIKELIHOOD OF SHORTWAVES TRACKING THROUGH THE FLOW RATHER HIGH. THE TRACK OF THESE WILL DEPEND ON HOW AMPLIFIED THE RIDGE BECOMES BUT LATEST GUIDANCE CONTINUES TO KEEP THE LOCAL AREA IN A FAVORED ZONE FOR THESE WAVES. THE AIRMASS WILL BECOME VERY MOIST BY THURSDAY WITH PRECIPITABLE WATER VALUES PUSHING/TOPPING 2 INCHES. BETWEEN THE POTENTIAL WAVES AND THE VERY MOIST AIRMASS SEVERAL ROUNDS OF THUNDERSTORMS MAY AFFECT THE FORECAST AREA FROM LATER WEDNESDAY THROUGH FRIDAY. IF THE AIRMASS BECOMES AS MOIST AS EXPECTED THEN ANY STORM WILL HAVE A GOOD CHANCE TO BRING HEAVY RAINFALL. RAINFALL POTENTIAL WILL NEED TO BE WATCHED CLOSELY OVER THE NEXT SEVERAL DAYS ESPECIALLY IF MULTIPLE ROUNDS LOOK MORE LIKELY. THIS RIDGE LOOKS TO AMPLIFY NORTHWARD SATURDAY PUSHING THE FAVORED STORM TRACK TO THE NORTH. EVOLUTION BEYOND SATURDAY IS MORE UNCERTAIN AND WILL BE DRIVEN BY THE MOVEMENT OF THE LARGE UPPER TROUGH OVER NORTHERN U.S. AND CANADIAN ROCKIES. GUIDANCE IS IN DISAGREEMENT ON HOW QUICKLY THIS OCCURS. OTHERWISE...HIGHS WILL WARM FROM MIDWEEK INTO THE WEEKEND AS WILL HUMIDITY LEVELS. THE WILD CARD WILL BE THUNDERSTORMS WITH THEIR TIMING AND LINGERING EFFECTS SUCH AS CLOUD COVER PLAYING A KEY ROLE IN HOW WARM THINGS GET. MINIMAL THUNDER IMPACT WOULD RESULT IN HIGHS IN THE MID AN UPPER 80S BY THURSDAY WITH 90 POSSIBLE...ESPECIALLY IF THE RIDGE AMPLIFIES MORE THAN CURRENTLY THOUGHT. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * CIGS AROUND 1,000 FEET LIKELY BECOMING IFR AGAIN THIS EVENING. * NELY WINDS TO ARND 10KT. KJB //DISCUSSION...UPDATED 19Z... BASED ON VISIBLE SATELLITE TRENDS EARLY THIS AFTERNOON...IT APPEARS LESS LIKELY THAT KORD...KMDW AND KGYY WILL SEE MUCH OF ANY ADDITIONAL IMPROVEMENT LATE THIS AFTERNOON AS PREVIOUSLY THOUGHT. THE NORTHEASTERLY FLOW CONTINUES TO PULL LOWER CLOUDS INTO NORTHEASTERN ILLINOIS AND THIS WILL LIKELY CONTINUE TO BE THE TREND TONIGHT. THEREFORE...CIGS LOOK TO LOWER BACK INTO THE IFR RANGE DURING THE EVENING AND LOSS OF DAYTIME HEATING. AREAS OF FOG COULD ALSO DEVELOP THIS EVENING...LEADING TO BOTH VERY LOW CIGS AND VISIBILITIES. //DISCUSSION...UPDATED 18Z... IFR CLOUDS CONTINUE TO STREAM IN OFF LAKE MICHIGAN THIS AFTERNOON UNDER NORTHEASTERLY FLOW. HOWEVER...AS TEMPERATURES SLOWLY WARM...CLOUD HEIGHTS ARE VERY SLOWLY LIFTING AT THE MAIN TERMINALS. IT APPEARS OVER THE NEXT FEW HOURS CLOUDS WILL HANG TOUGH ACROSS KORD AND KMDW...BUT WILL LIKELY INCREASE TO AROUND OR JUST ABOVE 1500 FEET BY MID AFTERNOON. HOWEVER...FARTHER INLAND AWAY FROM LAKE MICHIGAN...CONDITIONS WILL LIKELY IMPROVE QUICKER...WITH CLOUD COVER SCATTERING OUT IN SOME AREAS. LOOKING AHEAD TO TONIGHT...IT APPEARS THAT FOG COULD BECOME AN ISSUE...ESPECIALLY AFTER MIDNIGHT TONIGHT. WINDS ARE EXPECTED TO BECOME VERY LIGHT...AND WITH THE ABUNDANCE OF LOW LEVEL MOISTURE LOW VISIBILITIES IN FOG APPEAR TO BE A DECENT BET...ESPECIALLY AT KRFD AND KDPA. LOW CLOUDS AND VISIBILITIES ARE ALSO LIKELY AT THE EASTERN TERMINALS TONIGHT. CONDITIONS COULD AGAIN BE SLOW TO IMPROVE MONDAY MORNING...BUT CIGS SHOULD GRADUALLY BECOME VFR BY AFTERNOON. KJB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM WITH CIG TRENDS INTO THIS EVENING. * MEDIUM TO HIGH WITH WIND TRENDS. * MEDIUM TO HIGH WITH IFR CONDITIONS TONIGHT INTO MONDAY MORNING. KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT THROUGH FRIDAY NIGHT...PERIODIC CHANCES FOR SHRA/TSRA. OCNL MVFR CIGS/VIS POSSIBLE. SATURDAY...VFR. WX NIL. KREIN && .MARINE... 150 PM CDT A COLD FRONT HAS CLEARED THE SOUTHERN TIP OF THE LAKE...AND NORTH TO NORTHEAST WINDS HAVE OVERSPREAD LAKE MICHIGAN WITH HIGH PRESSURE OVER SOUTHERN ONTARIO AND LOW PRESSURE IN FAR SOUTHERN ILLINOIS. EXPECT WAVES TO BUILD GENERALLY INTO THE 2 TO 4 FT RANGE OVER THE SOUTHERN HALF OF THE LAKE BEFORE EASING SOME LATE TONIGHT. BOTH THE CANADIAN HIGH AND THE LOW IN SOUTHERN ILLINOIS WILL WORK THEIR WAY EASTWARD TONIGHT INTO MONDAY WHICH WILL SLACKEN THE WINDS AND VEER THEM TO MORE OF AN EASTERLY DIRECTION TONIGHT THAN SOUTH TO SOUTHEASTERLY ON MONDAY. ANOTHER WEAK LOW PASSING THROUGH THE CANADIAN PRAIRIES WILL WORK ITS WAY SE TOWARD THE NORTHERN HALF OF THE LAKE ON TUESDAY AND SLOWLY DRIFT EAST ON WEDNESDAY. AFTER A PERIOD OF HIGH PRESSURE...A SERIES OF WEAK LOWS WILL MIGRATE EASTWARD OUT OF THE PLAINS TOWARD THE LAKE FOR THE LATTER HALF OF THE WEEK. KMD && .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 300 PM CDT Sun Aug 17 2014 .SHORT TERM...(This evening through Monday) ISSUED AT 259 PM CDT SUN AUG 17 2014 Surface low has dropped into far southern Illinois early this afternoon with remnant MCV still evident on radar imagery over the far southeast CWA. This is where most of the lingering showers are continuing, with a few as far north as Taylorville and Tuscola. Some thinning of the low clouds has been developing but skies still mainly cloudy. Main concern for this part of the forecast is with fog potential tonight. Cloudiness across far northern Illinois and southeast Iowa is more cellular in nature and should diminish with loss of daytime heating. Latest RAP guidance showing the northern CWA becoming partly cloudy this evening. With northeast flow continuing, not a lot of drying will take place in the lower levels with dew points upstream still in the mid 60s in many areas. This should allow visibilities to start dropping by late evening across the north. Model guidance showing a fair range as to how extensive or thick the fog gets, so for now will only mention patchy or areas of fog in the grids for late tonight and early Monday. Skies expected to become partly to mostly sunny by midday as forecast soundings are rather dry. In terms of the lingering showers, most of what`s left in our area is along a weak trough axis dropping into southern Illinois, aided by the upper low which is currently located in far southwest Indiana. Am expecting the showers to fade early this evening as the low pulls away. On Monday, have maintained some isolated showers/ storms across the eastern CWA during the afternoon as a weak wave passes through the area. && .LONG TERM...(Monday night through Sunday) ISSUED AT 259 PM CDT SUN AUG 17 2014 Monday night will feature an upper trough and weak surface low tracking from the upper midwest into the western Great Lakes, with a cold front extending south into northern Illinois. Rain chances will return to areas NW of the I-55 later Monday evening, with chances expanding to Indiana along and north of I-72 by 12z/7am Tuesday. Better forcing from the 500mb vort max should remain in northern IL, but moisture convergence along the front and a weak 300mb jet max overhead could provide just enough lift for a few storms with the front. No severe weather is expected, especially with limited instability overnight. Tuesday should see a decreasing trend in rain/storm chances in the afternoon as the bulk of the mid and upper level energy departs to the east. The break in the rain should continue Tues night for all but the far southwest KILX CWA, from Jacksonville to Effingham, where a warm front will quickly approach the area. Rain/storm chances will remain mainly southwest of Havana to Lincoln to Shelbyville on Wednesday as the front slowly pushes into IL. That warm front is expected to usher in a progressively warmer airmass the remainder of the week and into the weekend. Wednesday night, an MCV is projected to move from N Iowa across N Illinois, with enough support from strong mid level warm air advection and a low level jet across central IL to trigger showers/storms across most of our forecast area. Low surface pressure and a stalled frontal boundary are still expected across northern Illinois for Thursday, keeping rain chances going into Thursday night. The front is expected wash out Thursday night as warming continues through a deep layer of the atmosphere. The warming at mid levels will eventually work to cap the atmosphere and limit storm potential, despite ample low level moisture. A shortwave is forecast by the ECMWF to move from Nebraska across N Illinois Saturday, which could affect our northern counties with a few storms, depending on the extent of elevated CAPE above the capping inversion. The ECMWF is also showing a cold frontal passage following the shortwave on Saturday night, bringing a period of storms and slightly cooler air for Sunday. The GFS keeps the upper level ridge entrenched over IL, limiting much storm potential by keeping shortwave tracks north of central IL. It also has much warmer conditions continuing into Sunday. Confidence remains low on the scenario for next weekend due to the differences. Heat and humidity levels will climb the last half of the week, as highs reach into the lower 90s south of Lincoln to Mattoon Thurs through Saturday. Dewpoints in the low to mid 70s will help push heat index readings into the upper 90s to around 100 in at least the south half of the KILX CWA. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 1235 PM CDT SUN AUG 17 2014 Still have some IFR conditions lingering at midday from KUIN east to near KCMI and north to KBMI, just north of a weak surface trough. Areas from about KPIA northward have seen some increase in ceilings with MVFR conditions lingering. Will continue to see some increase there, but think that MVFR conditions will be most prominent later this afternoon across central Illinois with an upper low in the southeast part of the state. Outlook for tonight will be tricky. Currently thinking that KPIA/KBMI may scatter out long enough to allow for rapid fog development toward 06Z and subsequent IFR conditions. Further south, have brought conditions down to around 2SM in visibility overnight, but am not as sure about widespread dense fog, since no substantial clearing is expected ahead of time. Low ceilings should start to lift mid to late Monday morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GEELHART LONG TERM...SHIMON AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 PM CDT SUN AUG 17 2014 .DISCUSSION... 1103 AM CDT CLOUD TRENDS REMAIN THE MAIN CHALLENGE THROUGH THE AFTERNOON FOLLOWED BY THEIR IMPACT ON TEMPS. LATEST SATELLITE IMAGES SHOWS SOME EROSION OF THE MOST WIDESPREAD STRATUS...ESPECIALLY INLAND OF THE LAKE. HOWEVER...STRATOCU IS BEGINNING TO DEVELOP IN THE LOWER COVERAGE AREAS AND MAY STRATIFY SOMEWHAT FOR A FEW HOURS THROUGH EARLY AFTERNOON BUT LIFT WITH TIME THEN ERODE LATER THIS AFTERNOON. FAR SOUTHERN AREAS WILL CONTINUE TO SEE CLOUD COVER FROM THE UPPER LOW TO THE SOUTH AND EAST AS WELL AS SOME LOW SHOWER POTENTIAL. STRATUS IS QUITE EXTENSIVE ACROSS LAKE MICHIGAN WITH TRAJECTORIES FEEDING THIS INTO WESTERN AND SOUTHERN SHORELINE AREAS. THIS WILL LIKELY RESULT IN AREAS NEAR THE LAKE REMAINING UNDER THE MORE WIDESPREAD CLOUD COVER LONGER AND IT IS TOUGH TO SAY HOW MUCH IMPROVEMENT MAY OCCUR THROUGH THE AFTERNOON. HAVE ADJUSTED TEMPS BASED ON LATEST TRENDS WITH MINOR DOWNWARD ADJUSTMENTS CLOSE TO THE LAKE. MDB //PREV DISCUSSION... 315 AM CDT SHORT TERM...THROUGH SUNDAY NIGHT... FOR THE REMAINDER OF THE NIGHT AND INTO SUNDAY MORNING...FORECAST CONCERNS WILL FOCUS ON THE COLD FRONT MOVING INTO NERN IL WHILE A SLOW MOVING SHORTWAVE MOVES OVER SRN IL. AS OF 08Z...THE BACK DOOR COLD FRONT HAS PUSHED THROUGH FAR NERN IL AND IS STEADILY PUSHING TO THE SOUTHWEST. THIS CLIMATOLOGICALLY UNUSUAL TYPE OF FRONTAL PASSAGE WILL TURN WINDS TO NELY OFF OF LAKE MICHIGAN AND USHER IN A LOWERING STRATUS DECK AND LOWER TEMPERATURES...ESPECIALLY FOR THE LAKEFRONT. LATEST RADAR IMAGERY INDICATES THAT THE BULK OF THE PCPN ASSOCIATED WITH THIS SYSTEM IS MOVING TO THE SOUTHEAST UNDER MODEST NWLY FLOW ALOFT...SO DO NOT ANTICIPATE MUCH PCPN TO FOLLOW THE FROPA...THOUGH A FEW ISOLD SPRINKLES ARE NOT OUT OF THE QUESTION. THE OTHER FEATURE OF CONCERN...THE SHORTWAVE PASSING OVER SRN IL IS STILL MOVING VERY SLOWLY THROUGH AN AREA OF WEAK FLOW ALOFT. THE BULK OF THE PCPN ASSOCIATED WITH THIS SYSTEM WILL REMAIN UNDER THE MAIN CIRCULATION CENTER...WELL TO THE SOUTH OF THE CWA...BUT THERE ARE STILL BANDS OF SHRA MOVING NWD ON THE NERN PERIPHERY OF THE SYSTEM. THESE SHOWERS SHOULD MOSTLY IMPACT LOCATIONS SOUTH OF THE I-80 CORRIDOR. THE AIRMASS IS STILL QUITE MOIST THROUGH A DEEP LAYER WITH THE 00Z ILX SOUNDING INDICATING PWAT OF 1.79 INCHES. AGAIN...THE HEAVIEST RAIN WILL REMAIN WELL SOUTH OF THE CWA...BUT GIVEN THE MOIST ENVIRONMENT IN PLACE...WITH WEAK FLOW ALOFT OVER THAT AREA...SOME OF THE HEAVIER SHOWERS OR A FEW THUNDERSTORMS COULD STILL PRODUCE SOME LOCALLY HEAVY RAINFALL TODAY. THE SHORTWAVE OVER SRN IL SHOULD CONTINUE TO TRACK SLOWLY TO THE EAST INTO THE OHIO VALLEY THIS EVENING...BRINGING AN END TO THE PCPN POTENTIAL FOR THE SRN PORTIONS OF THE CWA LATE SUNDAY NIGHT. AS FOR THE BACK DOOR COLD FRONT...THE INITIAL SURGE OF COOLER AIR WITH THE LOW STRATUS SHOULD PERSIST THROUGH THE MORNING. SINCE IT IS TECHNICALLY STILL SUMMER...DIURNAL HEATING SHOULD ALLOW THE STRATUS AND ANY RESIDUAL PATCHY FOG TO BURN OFF THROUGH THE LATE MORNING AND INTO THE EARLY AFTERNOON. UPPER LEVEL SHORT WAVE RIDGING SHOULD BUILD OVER THE AREA TODAY FOLLOWING THE PASSAGE OF THE SHORT WAVE INTO THE OHIO VALLEY...SO THERE WILL STILL BE OPPORTUNITY FOR INLAND TEMPERATURES TO REACH AROUND 80F. LOCATIONS INVOF LAKE MICHIGAN WILL REMAIN COOLER...WITH TEMPERATURES ALONG THE LAKEFRONT ONLY REACHING THE LOWER 70S AND INLAND LOCATIONS WITHIN 30 MILES OR SO OF THE LAKE ONLY REACHING THE MIDDLE 70S. OVERNIGHT TONIGHT...HIGH PRESSURE WITH BUILD ACROSS THE UPPER GREAT LAKES WITH A SFC RIDGE AXIS EXTENDING INTO NRN IL. A NORTHERN STREAM SHORTWAVE MOVING OVER MINNESOTA WILL SLOWLY EWD ACROSS WISCONSIN. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS...BUT ANY ASSOCIATED PCPN SHOULD REMAIN WELL NORTH OF THE WISCONSIN BORDER AND WILL LIKELY ONLY BRING INCREASING CLOUD COVER TO NRN IL/NWRN IN. KREIN MONDAY THROUGH TUESDAY... MAIN CONCERN IN THE MEDIUM TERM WILL BE ON THE DISSIPATING SHORTWAVE ACROSS THE OHIO VALLEY...WITH A SLIGHTLY MORE ROBUST AREA OF VORTICITY/TROUGH PIVOTING EAST ACROSS THE UPPER MIDWEST/WESTERN GREAT LAKES. IN THE WAKE OF THE OHIO VALLEY WAVE...IT APPEARS MUCH OF MON COULD END UP BEING RATHER QUIET/DRY WITH A WEAK BUMP IN THE SFC HEIGHTS/MID-LVL DIFFLUENCE. LAYERED RH STILL SUPPORTS CLOUDS AND THIS COUPLED WITH A LIGHT MAINLY EASTERLY FLOW AT THE SFC...AND TEMPS WILL LIKELY HOLD IN THE MID/UPR 70S WITH NEAR 80 FOR THE FAR WEST/SOUTH PORTIONS OF THE FORECAST AREA MON. BY MON EVE THE TROUGH AXIS OVER THE UPPER MIDWEST WILL BE NEARING THE CWFA. HEIGHTS LOWER WITH A STEADY MOISTENING IN THE COLUMN AND INSTABILITY CREEPING BACK INTO THE REGION. LOCAL ARW8KM SOLUTION HOLDS PRECIP OFF UNTIL AFT 6Z TUE IN THE WESTERN CWFA THEN SLOWLY SLIDES EAST BY DAYBREAK TUE. COULD SEE THIS SOLUTION VERIFYING IF THE WEAK BUMP IN HEIGHTS MON AFTN LINGERS OR IS SLIGHTLY STRONGER. FOR NOW WILL HEDGE SLIGHTLY TOWARDS THIS OUTCOME...AND HOLD ONTO SLT CHC/CHC POPS MON NGT. WITH STEADILY INCREASING LLVL MOISTURE AND CLOUDS MON NGT WILL LIKELY REMAIN MILD...WITH LOWS IN THE MID/UPR 60S. FOR TUE THE TROUGH WILL BE OVER THE WESTERN LAKES...WITH GUIDANCE BRINGING A BETTER DEFINED SFC FEATURE INTO THE UPPER PENINSULA TUE MORNING. THE BEST FORCING WILL BE CONFINED WELL NORTH OF THE CWFA...HOWEVER SOUNDINGS STILL SUPPORT ROUGHLY 1000J/KG IN A NARROW COLUMN ACROSS THE AREA. PWAT VALUES SHUD HOVER ARND 1.2-1.7"...SO NOT EXPECTING ANY HEAVY RAIN TO OCCUR TUE. TUE HIGHS SHUD BE A LITTLE WARMER WITH 850MB TEMPS PUSHING TO ARND 16-18 DEG C IN THE AFTN. SO EXPECT GENERALLY ARND 80 TO THE LOW 80S ACROSS THE FORECAST AREA. LLVL FLOW SHUD GENERALLY BE FROM THE S/SW AND KEEP ANY LAKE BREEZE CONFINED ALONG THE SHORELINE. WEDNESDAY THROUGH SATURDAY... FOR THE EXTENDED PERIODS THE FOCUS OF LATE HAS BEEN ON A PATTERN CHANGE FROM TROUGHING ACROSS THE GREAT LAKES REGION...BEING REPLACED WITH A MID-LVL RIDGE WITH MUCH WARMER TEMPS. ALTHOUGH THE CHALLENGE WILL BE HOW WARM GIVEN WHAT APPEARS TO BE A SOMEWHAT ACTIVE STRETCH...WHICH COULD FEATURE RIDGE-ROLLERS OR CONVECTIVE COMPLEXES THAT TRAVERSE THE TOP OF THE RIDGE. ENSEMBLES SOLUTIONS HAVE THE NORTH ATLANTIC RIDGE WEAKENING SLIGHTLY THEN RETROGRADING ACROSS NORTHERN QUEBEC AND EXPANDING SOUTHWEST WITH TIME. MEANWHILE RIDGING ACROSS THE EASTERN PACIFIC CONTINUES...ALLOWING TROUGHING TO BE DISPLACED FURTHER WEST ACROSS THE ROCKIES/SOUTHWEST CONUS LATER IN THE WEEK. THIS WILL SET THE STAGE FOR BROAD RIDING TO DEVELOP IN THE CENTRAL CONUS AND LIKELY ALLOW TEMPS TO STEADILY WARM. THE PLACEMENT OF THE MID-LVL RIDGE WILL STEER THE PLACEMENT OF CONVECTION/PRECIP. SOME CONSISTENCY REMAINS THAT THE ACTIVE WEATHER WILL LIKELY FALL ACROSS THE CWFA...WHICH COULD KEEP TEMPS FROM GETTING TOO WARM. ALTHOUGH IF THE RIDGE IS SLIGHTLY STRONGER AND CENTERED FURTHER NORTH...THIS COULD PUSH THE ACTIVE ZONE NORTH INTO WISC AND ALLOW OUR TEMPS TO BE MUCH WARMER IN THE UPR 80S TO PERHAPS A FEW 90 DEG READINGS LATE IN THE WEEK. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * CIGS AROUND 1,000 FEET LIKELY BECOMING IFR AGAIN THIS EVENING. * NELY WINDS TO ARND 10KT. KJB //DISCUSSION...UPDATED 19Z... BASED ON VISIBLE SATELLITE TRENDS EARLY THIS AFTERNOON...IT APPEARS LESS LIKELY THAT KORD...KMDW AND KGYY WILL SEE MUCH OF ANY ADDITIONAL IMPROVEMENT LATE THIS AFTERNOON AS PREVIOUSLY THOUGHT. THE NORTHEASTERLY FLOW CONTINUES TO PULL LOWER CLOUDS INTO NORTHEASTERN ILLINOIS AND THIS WILL LIKELY CONTINUE TO BE THE TREND TONIGHT. THEREFORE...CIGS LOOK TO LOWER BACK INTO THE IFR RANGE DURING THE EVENING AND LOSS OF DAYTIME HEATING. AREAS OF FOG COULD ALSO DEVELOP THIS EVENING...LEADING TO BOTH VERY LOW CIGS AND VISIBILITIES. //DISCUSSION...UPDATED 18Z... IFR CLOUDS CONTINUE TO STREAM IN OFF LAKE MICHIGAN THIS AFTERNOON UNDER NORTHEASTERLY FLOW. HOWEVER...AS TEMPERATURES SLOWLY WARM...CLOUD HEIGHTS ARE VERY SLOWLY LIFTING AT THE MAIN TERMINALS. IT APPEARS OVER THE NEXT FEW HOURS CLOUDS WILL HANG TOUGH ACROSS KORD AND KMDW...BUT WILL LIKELY INCREASE TO AROUND OR JUST ABOVE 1500 FEET BY MID AFTERNOON. HOWEVER...FARTHER INLAND AWAY FROM LAKE MICHIGAN...CONDITIONS WILL LIKELY IMPROVE QUICKER...WITH CLOUD COVER SCATTERING OUT IN SOME AREAS. LOOKING AHEAD TO TONIGHT...IT APPEARS THAT FOG COULD BECOME AN ISSUE...ESPECIALLY AFTER MIDNIGHT TONIGHT. WINDS ARE EXPECTED TO BECOME VERY LIGHT...AND WITH THE ABUNDANCE OF LOW LEVEL MOISTURE LOW VISIBILITIES IN FOG APPEAR TO BE A DECENT BET...ESPECIALLY AT KRFD AND KDPA. LOW CLOUDS AND VISIBILITIES ARE ALSO LIKELY AT THE EASTERN TERMINALS TONIGHT. CONDITIONS COULD AGAIN BE SLOW TO IMPROVE MONDAY MORNING...BUT CIGS SHOULD GRADUALLY BECOME VFR BY AFTERNOON. KJB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM WITH CIG TRENDS INTO THIS EVENING. * MEDIUM TO HIGH WITH WIND TRENDS. * MEDIUM TO HIGH WITH IFR CONDITIONS TONIGHT INTO MONDAY MORNING. KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT THROUGH FRIDAY NIGHT...PERIODIC CHANCES FOR SHRA/TSRA. OCNL MVFR CIGS/VIS POSSIBLE. SATURDAY...VFR. WX NIL. KREIN && .MARINE... 150 PM CDT A COLD FRONT HAS CLEARED THE SOUTHERN TIP OF THE LAKE...AND NORTH TO NORTHEAST WINDS HAVE OVERSPREAD LAKE MICHIGAN WITH HIGH PRESSURE OVER SOUTHERN ONTARIO AND LOW PRESSURE IN FAR SOUTHERN ILLINOIS. EXPECT WAVES TO BUILD GENERALLY INTO THE 2 TO 4 FT RANGE OVER THE SOUTHERN HALF OF THE LAKE BEFORE EASING SOME LATE TONIGHT. BOTH THE CANADIAN HIGH AND THE LOW IN SOUTHERN ILLINOIS WILL WORK THEIR WAY EASTWARD TONIGHT INTO MONDAY WHICH WILL SLACKEN THE WINDS AND VEER THEM TO MORE OF AN EASTERLY DIRECTION TONIGHT THAN SOUTH TO SOUTHEASTERLY ON MONDAY. ANOTHER WEAK LOW PASSING THROUGH THE CANADIAN PRAIRIES WILL WORK ITS WAY SE TOWARD THE NORTHERN HALF OF THE LAKE ON TUESDAY AND SLOWLY DRIFT EAST ON WEDNESDAY. AFTER A PERIOD OF HIGH PREESURE...A SERIES OF WEAK LOWS WILL MIGRATE EASTWARD OUT OF THE PLAINS TOWARD THE LAKE FOR THE LATTER HALF OF THE WEEK. KMD && .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 300 PM CDT Sun Aug 17 2014 .SHORT TERM...(This evening through Monday) ISSUED AT 259 PM CDT SUN AUG 17 2014 Surface low has dropped into far southern Illinois early this afternoon with remnant MCV still evident on radar imagery over the far southeast CWA. This is where most of the lingering showers are continuing, with a few as far north as Taylorville and Tuscola. Some thinning of the low clouds has been developing but skies still mainly cloudy. Main concern for this part of the forecast is with fog potential tonight. Cloudiness across far northern Illinois and southeast Iowa is more cellular in nature and should diminish with loss of daytime heating. Latest RAP guidance showing the northern CWA becoming partly cloudy this evening. With northeast flow continuing, not a lot of drying will take place in the lower levels with dew points upstream still in the mid 60s in many areas. This should allow visibilities to start dropping by late evening across the north. Model guidance showing a fair range as to how extensive or thick the fog gets, so for now will only mention patchy or areas of fog in the grids for late tonight and early Monday. Skies expected to become partly to mostly sunny by midday as forecast soundings are rather dry. In terms of the lingering showers, most of what`s left in our area is along a weak trough axis dropping into southern Illinois, aided by the upper low which is currently located in far southwest Indiana. Am expecting the showers to fade early this evening as the low pulls away. On Monday, have maintained some isolated showers/ storms across the eastern CWA during the afternoon as a weak wave passes through the area. && .LONG TERM...(Monday night through Sunday) ISSUED AT 259 PM CDT SUN AUG 17 2014 Monday night will feature an upper trough and weak surface low tracking from the upper midwest into the western Great Lakes, with a cold front extending south into northern Illinois. Rain chances will return to areas NW of the I-55 later Monday evening, with chances expanding to Indiana along and north of I-72 by 12z/7am Tuesday. Better forcing from the 500mb vort max should remain in northern IL, but moisture convergence along the front and a weak 300mb jet max overhead could provide just enough lift for a few storms with the front. No severe weather is expected, especially with limited instability overnight. Tuesday should see a decreasing trend in rain/storm chances in the afternoon as the bulk of the mid and upper level energy departs to the east. The break in the rain should continue Tues night for all but the far southwest KILX CWA, from Jacksonville to Effingham, where a warm front will quickly approach the area. Rain/storm chances will remain mainly southwest of Havana to Lincoln to Shelbyville on Wednesday as the front slowly pushes into IL. That warm front is expected to usher in a progressively warmer airmass the remainder of the week and into the weekend. Wednesday night, an MCV is projected to move from N Iowa across N Illinois, with enough support from strong mid level warm air advection and a low level jet across central IL to trigger showers/storms across most of our forecast area. Low surface pressure and a stalled frontal boundary are still expected across northern Illinois for Thursday, keeping rain chances going into Thursday night. The front is expected wash out Thursday night as warming continues through a deep layer of the atmosphere. The warming at mid levels will eventually work to cap the atmosphere and limit storm potential, despite ample low level moisture. A shortwave is forecast by the ECMWF to move from Nebraska across N Illinois Saturday, which could affect our northern counties with a few storms, depending on the extent of elevated CAPE above the capping inversion. The ECMWF is also showing a cold frontal passage following the shortwave on Saturday night, bringing a period of storms and slightly cooler air for Sunday. The GFS keeps the upper level ridge entrenched over IL, limiting much storm potential by keeping shortwave tracks north of central IL. It also has much warmer conditions continuing into Sunday. Confidence remains low on the scenario for next weekend due to the differences. Heat and humidity levels will climb the last half of the week, as highs reach into the lower 90s south of Lincoln to Mattoon Thurs through Saturday. Dewpoints in the low to mid 70s will help push heat index readings into the upper 90s to around 100 in at least the south half of the KILX CWA. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 1235 PM CDT SUN AUG 17 2014 Still have some IFR conditions lingering at midday from KUIN east to near KCMI and north to KBMI, just north of a weak surface trough. Areas from about KPIA northward have seen some increase in ceilings with MVFR conditions lingering. Will continue to see some increase there, but think that MVFR conditions will be most prominent later this afternoon across central Illinois with an upper low in the southeast part of the state. Outlook for tonight will be tricky. Currently thinking that KPIA/KBMI may scatter out long enough to allow for rapid fog development toward 06Z and subsequent IFR conditions. Further south, have brought conditions down to around 2SM in visibility overnight, but am not as sure about widespread dense fog, since no substantial clearing is expected ahead of time. Low ceilings should start to lift mid to late Monday morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GEELHART LONG TERM...SHIMON AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS TOPEKA KS
644 PM CDT Mon Aug 18 2014 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Tuesday) Issued at 352 PM CDT MON AUG 18 2014 The center of an upper level trough was located across eastern ND late this afternoon with an upper level trough axis extending southwest across central SD. The numerical models show this upper level trough digging southeast across southern MN and eastern NE into northern MO. The southwest section of the upper trough will move southeast across northeast KS between 6Z and 12Z. The NAM, GFS and ECMWF forecast QPF across northeast and east central KS later Tonight, with the ECMWF and NAM showing most of the CWA with QPF. The NAM model shows weak isentropic lift at the 310K level with LFCs around 700mb. The most intense isentropic lift at the 310K level will be across northern MO and IA. The mesoscale models, consisting of the ARW, NMM and HRRR do not forecast any QPF across the CWA tonight. I will probably keep slight chance to chance pops across much of the CWA, since the ascent ahead of the H5 trough combined with isentropic lift should allow elevated thunderstorms to develop across the northeast counties of the CWA around midnight, then building southwest across the central and southwest counties of the CWA through the early morning hours before spreading southeast across much of east central KS by 12Z TUE. Any lingering elevated thunderstorms, if they do develop, will shift southeast of the CWA during the mid morning hours. Skies should clear through the late morning and early afternoon hours and temperatures will warm into the lower to mid 90s. If there is a leftover outflow boundary across the northeast counties, then temperatures along the NE border may only reach into the upper 80s. I placed in 14 pops in case there is enough surface convergence for an isolated thunderstorm during the afternoon hours. .LONG TERM...(Tuesday Night through Monday) Issued at 352 PM CDT MON AUG 18 2014 Models are in agreement that heights rises and resulting warm air advection will be situated across the northeast corner of the county warning area Tuesday evening providing another chance for thunderstorms. As this area focuses further northward through the night...have removed pops this area after midnight. Will keep lows mild in the low to middle 70s. This will then set the stage for mostly sunny very warm...breezy day on Wednesday. Highs will generally be 95 to 100 degrees with the warmest in the Abilene area and the coolest near Hiawatha. As the upper ridge builds across the southern plains...expect dry weather across the cwa Wednesday night through Thursday. However... with south winds continuing...highs Thursday will again be in the middle to upper 90s. As the cutoff upper trough in the desert southwest gets picked up by Thursday and heads into the central and northern high plains into the weekend...there will be better chances for thunderstorms across the area...although the northern/northwest 1/2 of the cwa will be the more likely areas to see rain. Do not expect a frontal passage until during the day Sunday...so may not see highs temps below 90 degrees until Monday when readings in the middle to upper 80s should be the rule. && .AVIATION...(For the 00Z TAFs through 00Z Tuesday Evening) Issued at 626 PM CDT MON AUG 18 2014 VFR conditions prevail at sites as new guidance is increasing confidence for VCTS mention for scattered TSRA to form along and north of a frontal boundary near the terminals. Best timing for convection in vicinity of terminals is from 06Z to 13Z. Isolated strong wind gusts are possible. VRB winds persist near the boundary axis shifting towards the southeast during the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...63 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
610 PM CDT Mon Aug 18 2014 ...Updated aviation discussion... .SHORT TERM...(This evening through Tuesday) ISSUED AT 1202 PM CDT MON AUG 18 2014 There is a high pressure ridge over Colorado south into New Mexico late this afternoon. A lee side trough is near the Kansas and Colorado border, and a warm front has been pushing northeast through western Kansas this morning. The forecast is on track for today, with highs just over 100F degrees likely somewhere across southern and western Kansas, and upper 90s in our northern zones. There could be a few and far between showers and isolated thunderstorms just about anywhere late today. The HRRR model shows a few thunderstorms across our south and southeast zones after 21z, but the NAM and NAMNG5 models are showing storms first over our west and then moving across the northern CWA. Mid and high clouds will be on the increase late this afternoon and evening. So, the low Pops in the 17-20 percent range blanketing our forecast area seem reasonable. Time will tell on which model is more correct. The same HRRR, NAM, and NAMNG5 models decrease the measurable precip after 04Z, and then the clouds will slowly dissipate after 09Z or so. I plan to reduce 20 percent Pops rapidly between 06Z and 12Z. Not much precipitation will fall either, as any convection will be high based. I used the QPF_from_PoP application, and it only shows 0.01 to spotty 0.03 inches of rain overnight. With clouds breaking late and perhaps a little rain, minimum temperatures should end up in the middle 60s in Syracuse, Scott City, and Wakeeney, while settling only to around 70F degrees in the Meade, Coldwater and Medicine Lodge areas. Winds will continue to hover at less than 10 MPH tonight. On Tuesday, the surface low will advect into central Kansas, and the front will sag south across part of our CWA. Thus, Max temps should dip just a little north of the front, while south along the Oklahoma border near Medicine Lodge, it should warm up to around 100F. Winds on Tuesday will be breezy from the south in the 15 to 25 mph and gusty range. I do not think there will any precipitation on Tuesday, as the lower max temps will result in less instability than today. .LONG TERM...(Tuesday night through Monday) ISSUED AT 225 PM CDT MON AUG 18 2014 Medium range models indicate an upper level ridge of high pressure transitioning eastward out of the Western High Plains into the Central Plains to begin the period Tuesday night. Combined with a weak flow aloft, drier conditions are likely to prevail through late Wednesday afternoon. Meanwhile, an upper level trough will dig southeast across southern California Wednesday setting up a strong southwest flow aloft across the Central and Southern Rockies, including a +90kt jet core projected to lift northeast out of the Desert Southwest into the Colorado Rockies. With a prevailing lee side trough providing increased convergence in the lower levels, thunderstorm development is likely across portions of eastern Colorado Wednesday afternoon with a few storms potentially drifting into western Kansas later in the evening through early Thursday. However, the weaker flow aloft across western Kansas will limit the strength and coverage of any storms. The upper level shortwave will then lift northeast going into the weekend while a large scale upper level high remains locked in across the Deep South. Although precip chances will remain present virtually each day into the weekend, the weaker flow aloft will limit storm development, strength, and coverage. Temperatures will remain above normal Wednesday as the aforementioned upper level ridge shifts east across the Central Plains. A prevailing southerly flow across western Kansas will reinforce the warmer air mass already in place across the region with H85 temperatures ranging from the upper 20s(C) in central Kansas to around 30C closer to the Colorado border. As lower level lapse rates steepen into the afternoon, look for highs well up into the 90s(F) to near 100F Wednesday. Similar temperatures are then expected each day through Saturday as the low level southerly flow persists into the early part of the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 607 PM CDT MON AUG 18 2014 VFR conditions are expected overnight and Tuesday based on the moisture profiles from the 18z NAM BUFR soundings. Ongoing diurnally driven convection near GCK and DDC will dissipate by or shortly after sunset. There will be another chance for convection after 03z as an upper level disturbance crosses western Kansas. At this time given the latest NAM, RAP, and HRRR the probability for convection after 03z at GCK, DDC, or HYS still appears small so will not include mention of a prevailing group of convection in the 00z tafs. Will place VCTS in the HYS tafs for several hours, mainly between 04z and 08z. Prevailing winds will be south/southwest at around 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 69 97 71 99 / 30 10 0 10 GCK 67 96 70 98 / 30 10 0 10 EHA 66 95 68 98 / 30 10 0 20 LBL 66 96 71 98 / 30 10 0 10 HYS 68 98 71 99 / 20 10 0 10 P28 70 98 74 99 / 50 10 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Burke LONG TERM...JJohnson AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
227 PM MDT SUN AUG 17 2014 .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 121 PM MDT SUN AUG 17 2014 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS CONTINUE TO SHOW PERSISTENT RIDGE IN PLACE ACROSS THE SW US. A SHORTWAVE TROUGH IS EVIDENT OVER NORTHERN COLORADO...WITH H7 TROUGH ON LATEST RAP JUST OVER THE CENTRAL ROCKIES. RADAR AND VIS SATELLITE SHOW ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ALREADY DEVELOPING ALONG SURFACE TROUGH AXIS AHEAD OF UPPER TROUGH OVER OUR SW CWA. HRRR HAS A REASONABLE HANDLE ON CURRENT COVERAGE AND INDICATED ACTIVITY MAINLY REMAINING ALONG AND EAST OF A TRIBUNE TO FLAGLER LINE. MODERATE INSTABILITY IS IN PLACE WITH ML CAPE IN THE 1500- 3000 J/KG RANGE. CIN IS STILL HIGH ACROSS THE EASTERN HALF OF THE CWA...HOWEVER AS SHORTWAVE TROUGH MOVES EAST LATER THIS AFTERNOON AND EVENING ML CINH SHOULD WEAKEN ALLOWING FOR ACTIVITY TO SPREAD EASTWARD. COVERAGE IS STILL A QUESTION WITH DRY INVERTED V TYPE MOISTURE PROFILES...HOWEVER WITH LARGE SCALE FORCING INCREASE AND GOOD BL MOISTURE IN PLACE WE SHOULD BE ABLE TO SEE SCATTERED ACTIVITY DEVELOP. THERE IS AT LEAST AN ELEVATED SEVERE THREAT CONSIDERING THE FAVORABLE CAPE AND EXPECTATION OF EFFECTIVE SHEER INCREASING LATER THIS AFTERNOON/EVENING AS TROUGH MOVES INTO THE REGION. PROFILES WOULD ALSO SUPPORT POTENTIAL FOR MICROBURST POTENTIAL...WHICH IS ALSO SUPPORTED BY DCAPE VALUES AROUND 1800 J/KG. AS SHORTWAVE TROUGH SHIFTS EAST A WEAK FRONTAL PASSAGE WILL SLIGHTLY COOL TEMPS ALOFT TONIGHT AND PRECIP SHOULD COME TO AN END ACROSS THE EAST AFTER MIDNIGHT. MONDAY...WITH ELEVATED FRONT ACROSS THE NORTH...AND WASHED OUT FRONT/SURFACE BAROCLINIC ZONE IN THE SOUTH THUNDERSTORM REDEVELOPMENT WILL BE POSSIBLE ACROSS THE CWA MONDAY AFTERNOON. ANOTHER WEAK VORTICITY MAX WILL ROTATE JUST NORTH OF THE CWA MONDAY AFTERNOON/EVENING...WHICH COULD ALSO HELP WITH THUNDERSTORM INITIATION. PRECIP SIGNAL IS STRONGEST ACROSS THE SOUTHERN CWA THROUGH MONDAY AFTERNOON ALONG BAROCLINIC ZONE AS IS LIFTS NORTH...WITH BETTER COVERAGE TOWARDS LATE AFTERNOON IN THE SOUTH. HIGH TEMPS MONDAY SHOULD BE SLIGHTLY COOLER THAN TODAY...THOUGH THEY WILL REMAIN ABOVE NORMAL WITH MOST LOCATIONS IN THE LOW-MID 90S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 227 PM MDT SUN AUG 17 2014 SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE ACROSS THE REGION MONDAY EVENING BEFORE COMING TO AN END EARLY TUESDAY MORNING. AT FIRST...MAIN ACTIVITY SHOULD MOVE IN FROM NORTH CENTRAL COLORADO UNDER WEST-NORTHWEST FLOW. GFS CONDENSATION PRESSURE DEFICITS AND WINDS AT 320K INDICATE THAT ADDITIONAL ELEVATED STORM DEVELOPMENT IS POSSIBLE BY MIDNIGHT AS MAIN SHORTWAVE TROUGH PASSES THROUGH. DECIDED TO KEEP CHANCE POPS GOING THROUGH MOST OF THE NIGHT BEFORE WANING EARLY TUESDAY MORNING...BETWEEN 3-6 AM MDT. SOME OF THESE STORMS COULD BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS AS THE MAIN THREAT...TRANSITIONING TO PRIMARILY A LARGE HAIL THREAT WITH THE OVERNIGHT ELEVATED THUNDERSTORM ACTIVITY. THROUGH THE REST OF THE EXTENDED FORECAST PERIOD...A PERSISTENT UPPER LEVEL PATTERN IS THE MAIN STORY BEFORE A PACIFIC NORTHWEST TROUGH BREAKS THE RIDGE DOWN TOWARDS NEXT WEEKEND. FOR EACH DAY... SHOWERS AND STORMS ARE POSSIBLE AS WEAK UPPER LEVEL DISTURBANCES PASS OVER THE NORTHERN PERIPHERY OF THE SOUTHWESTERN U.S. RIDGE. STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY WITH CAPE OF 2000-2500J/KG ALONG AND NORTH OF INTERSTATE 70...850-500 MB LAPSE RATES AROUND 8 C/KM AND 0-6 KM BULK SHEAR AROUND 30-35 KTS. SOME DRIER BOUNDARY LAYER AIR MOVES INTO THE REGION FROM THE WEST FOR WEDNESDAY AND THURSDAY...LIMITING SEVERE CHANCES SOME BY DECREASING AVAILABLE MOISTURE AND ATMOSPHERIC INSTABILITY. AS FOR TEMPERATURES...HOT WEATHER IS EXPECTED TO PERSIST UNTIL THE RIDGE BEGINS TO BREAK DOWN NEXT WEEKEND. DID LOWER MIN TEMPERATURES A TOUCH BELOW MODEL GUIDANCE BASED ON RECENT TRENDS OBSERVED AND COOL THUNDERSTORM OUTFLOWS LIKELY EACH EVENING. MODEL GUIDANCE... ESPECIALLY THE EUROPEAN...SUGGESTS THAT A COLD FRONT PASSAGE IS POSSIBLE BY THE END OF THE WEEK. MODEL AGREEMENT IS FAIRLY POOR WITH THE GFS SUGGESTING THE HOT WEATHER WILL REMAIN. THEREFORE...DID NOT MAKE ANY LARGE CHANGES TO THE EXTENDED FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1139 AM MDT SUN AUG 17 2014 VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT BOTH KGLD AND KMCK TERMINALS. MAIN CONCERN IS THUNDERSTORMS EXPECTED TO DEVELOP ALONG KS/CO STATE LINE AND WITHIN VICINITY OF KGLD...EVENTUALLY INCREASING IN COVERAGE AS DISTURBANCE MOVES NORTH. SHORT RANGE GUIDANCE FAVORS KGLD FOR NOW...WITH LESS CONFIDENCE AT KMCK...SO I LIMITED TEMPO -TSRA TEMPO TO KGLD. GUSTY WINDS AROUND 15-20KT WILL CONTINUE THIS AFTERNOON ON EASTERN EDGE OF SURFACE TROUGH AT KMCK WITH LIGHTER WINDS GENERALLY AROUND 6KT AT KMCK. WILL WILL DIMINISH AT KMCK THIS EVENING WITH LOSS OF DAYTIME HEATING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...RRH AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
122 PM MDT SUN AUG 17 2014 .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 121 PM MDT SUN AUG 17 2014 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS CONTINUE TO SHOW PERSISTENT RIDGE IN PLACE ACROSS THE SW US. A SHORTWAVE TROUGH IS EVIDENT OVER NORTHERN COLORADO...WITH H7 TROUGH ON LATEST RAP JUST OVER THE CENTRAL ROCKIES. RADAR AND VIS SATELLITE SHOW ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ALREADY DEVELOPING ALONG SURFACE TROUGH AXIS AHEAD OF UPPER TROUGH OVER OUR SW CWA. HRRR HAS A REASONABLE HANDLE ON CURRENT COVERAGE AND INDICATED ACTIVITY MAINLY REMAINING ALONG AND EAST OF A TRIBUNE TO FLAGLER LINE. MODERATE INSTABILITY IS IN PLACE WITH ML CAPE IN THE 1500- 3000 J/KG RANGE. CIN IS STILL HIGH ACROSS THE EASTERN HALF OF THE CWA...HOWEVER AS SHORTWAVE TROUGH MOVES EAST LATER THIS AFTERNOON AND EVENING ML CINH SHOULD WEAKEN ALLOWING FOR ACTIVITY TO SPREAD EASTWARD. COVERAGE IS STILL A QUESTION WITH DRY INVERTED V TYPE MOISTURE PROFILES...HOWEVER WITH LARGE SCALE FORCING INCREASE AND GOOD BL MOISTURE IN PLACE WE SHOULD BE ABLE TO SEE SCATTERED ACTIVITY DEVELOP. THERE IS AT LEAST AN ELEVATED SEVERE THREAT CONSIDERING THE FAVORABLE CAPE AND EXPECTATION OF EFFECTIVE SHEER INCREASING LATER THIS AFTERNOON/EVENING AS TROUGH MOVES INTO THE REGION. PROFILES WOULD ALSO SUPPORT POTENTIAL FOR MICROBURST POTENTIAL...WHICH IS ALSO SUPPORTED BY DCAPE VALUES AROUND 1800 J/KG. AS SHORTWAVE TROUGH SHIFTS EAST A WEAK FRONTAL PASSAGE WILL SLIGHTLY COOL TEMPS ALOFT TONIGHT AND PRECIP SHOULD COME TO AN END ACROSS THE EAST AFTER MIDNIGHT. MONDAY...WITH ELEVATED FRONT ACROSS THE NORTH...AND WASHED OUT FRONT/SURFACE BAROCLINIC ZONE IN THE SOUTH THUNDERSTORM REDEVELOPMENT WILL BE POSSIBLE ACROSS THE CWA MONDAY AFTERNOON. ANOTHER WEAK VORTICITY MAX WILL ROTATE JUST NORTH OF THE CWA MONDAY AFTERNOON/EVENING...WHICH COULD ALSO HELP WITH THUNDERSTORM INITIATION. PRECIP SIGNAL IS STRONGEST ACROSS THE SOUTHERN CWA THROUGH MONDAY AFTERNOON ALONG BAROCLINIC ZONE AS IS LIFTS NORTH...WITH BETTER COVERAGE TOWARDS LATE AFTERNOON IN THE SOUTH. HIGH TEMPS MONDAY SHOULD BE SLIGHTLY COOLER THAN TODAY...THOUGH THEY WILL REMAIN ABOVE NORMAL WITH MOST LOCATIONS IN THE LOW-MID 90S. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 125 AM MDT SUN AUG 17 2014 THERE ARE STILL DIFFERENCES IN THE DETERMINISTIC AND ENSEMBLE OUTPUT BUT THEY ARE MUCH LESS THAN YESTERDAY. IN GENERAL THE MODELS DO AGREE ON THE OVERALL PATTERN OF HAVING A MEAN WESTERN TROUGH AND A STRONG RIDGE OVER THE SOUTHEAST PORTION OF THE COUNTRY. THIS DOES MAKE SENSE CONSIDERING THE CURRENT AMPLIFIED/BLOCKY PATTERN WE ARE NOW IN. THERE ARE TIMING DIFFERENCES...WITH THE ECMWF AND GFS IN MORE AGREEMENT...WITH THE TIMING/AMPLITUDE OF THE INDIVIDUAL WAVES. THE GFS IS FASTER AND LESS AMPLIFIED THAN THE ECMWF. NO MATTER WHAT THOUGH THIS PATTERN LEAVES THE AREA OPEN TO SHORTWAVES ROTATING THROUGH WITH SUBTROPICAL MOISTURE NEAR OR OVER THE AREA. THE ECMWF IS A LITTLE WETTER THAN THE GFS. SO DO LIKE WHAT THE CRH_INIT GAVE ME WITH THUNDERSTORM CHANCES EVERY DAY UNTIL SATURDAY WHEN IT LOOKS LIKE WE MAY DRY OUT. HOWEVER COULD SEE SATURDAY HAVING SOME LOW CHANCE OF THUNDERSTORMS. WILL LEAVE SATURDAY DRY FOR NOW SINCE IT IS A WEEK OUT PLUS THE MODELS ARE SHOWING ENOUGH DRYING TO SUPPORT THE DRY FORECAST. ALSO THIS PATTERN SUPPORTS THE CONTINUED HOT AND ABOVE NORMAL TEMPERATURES GIVEN TO ME BY THE INIT. THERE MAY BE A LITTLE COOL DOWN TOWARD THE END THOUGH. SO OVERALL PLAN ON LITTLE IF ANY CHANGES TO THE INIT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1139 AM MDT SUN AUG 17 2014 VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT BOTH KGLD AND KMCK TERMINALS. MAIN CONCERN IS THUNDERSTORMS EXPECTED TO DEVELOP ALONG KS/CO STATE LINE AND WITHIN VICINITY OF KGLD...EVENTUALLY INCREASING IN COVERAGE AS DISTURBANCE MOVES NORTH. SHORT RANGE GUIDANCE FAVORS KGLD FOR NOW...WITH LESS CONFIDENCE AT KMCK...SO I LIMITED TEMPO -TSRA TEMPO TO KGLD. GUSTY WINDS AROUND 15-20KT WILL CONTINUE THIS AFTERNOON ON EASTERN EDGE OF SURFACE TROUGH AT KMCK WITH LIGHTER WINDS GENERALLY AROUND 6KT AT KMCK. WILL WILL DIMINISH AT KMCK THIS EVENING WITH LOSS OF DAYTIME HEATING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
138 AM MDT SUN AUG 17 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 230 PM MDT SAT AUG 16 2014 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS 595 DM RIDGE CENTERED OVER SW US...WITH DIFFLUENT FLOW OVER THE NORTHERN PLAINS AHEAD OF A CLOSED LOW OVER THE SOUTHERN CANADIAN ROCKIES. AT THE SURFACE A COLD FRONT THAT MOVED INTO THE CWA LAST NIGHT ANS SHIFTED EAST WITH WEAK CONVERGENCE ALONG A TROUGH AXIS EXTENDING ACROSS EASTERN COLORADO. MODERATE INSTABILITY IS IN PLACE ACROSS THE EASTERN HALF OF THE CWA WITH ML CAPE VALUES IN THE 1000-2000 J/KG RANGE. LOWER VALUES AROUND 500 J/KG ARE IN PLACE ALONG THE TROUGH AXIS WHERE BETTER FOCUS FOR THUNDERSTORM INITIATION IS EXPECTED. HIGHER CINH WAS EXPECTED TO LIMIT INITIATION IN THE EAST...HOWEVER EXTENSIVE CU FIELD NOW IN PLACE WITH BETTER VERTICAL EXTENT THAT WOULD BE EXPECTED IF AIR MASS WAS COMPLETELY INHIBITED. WHERE THUNDERSTORMS HAVE DEVELOPED IN THE WEST WILL REMAIN MOST LIKELY AREA FOR CONVECTION ALONG WEAK CONVERGENCE ZONE...HOWEVER I COULDNT RULE OUT ISOLATED THUNDERSTORM ACTIVITY FURTHER EAST WERE CAP TO WEAKEN...ESPECIALLY WITH WESTERN EDGE OF FRONT NEAR OUR EASTERN CWA BORDER. HAVE EXTENDED AREA OF SLIGHT CHANCE POPS AND BUMPED UP COVERAGE IN THE SW. SEVERE THREAT REMAINS VERY LOW WITH WEAK SHEER...HOWEVER IF A BETTER UPDRAFT WERE TO DEVELOP IN THE EAST WHERE BETTER CAPE PROFILES EXIST THEN SEVERE HAIL/WIND COULD BE THREATS. BETTER THUNDERSTORM COVERAGE IS EXPECTED BY MID-LATE AFTERNOON SUNDAY AS A WEAK SHORTWAVE MOVES JUST NORTH OF THE CWA. MODELS HAVE A DECENT PRECIP SIGNAL OVER OUR CWA...DESPITE DRY SOUNDINGS...SO CHANCE POPS WERE RETAINED. THUNDERSTORMS WILL TEND TO BE ELEVATED..HOWEVER EFFECTIVE SHEER AROUND 35KT AND MODERATE MU CAPE IN THE 2000-2600 J/KG WOULD BE SUPPORTIVE OF A ELEVATED SEVERE WIND/HAIL THREAT WITH STORMS THAT DEVELOP. WIND MAY ACTUALLY BE THE GREATER THREAT CONSIDERING THE INVERTED V PROFILES IN PLACE. SOUTHERLY FLOW SHOULD BRING GOOD WAA BACK TO THE CWA...AND TEMPS SHOULD BE AS WARM IF NOT WARMER AS TODAY WITH VALUES IN THE MID- UPPER 90S. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 125 AM MDT SUN AUG 17 2014 THERE ARE STILL DIFFERENCES IN THE DETERMINISTIC AND ENSEMBLE OUTPUT BUT THEY ARE MUCH LESS THAN YESTERDAY. IN GENERAL THE MODELS DO AGREE ON THE OVERALL PATTERN OF HAVING A MEAN WESTERN TROUGH AND A STRONG RIDGE OVER THE SOUTHEAST PORTION OF THE COUNTRY. THIS DOES MAKE SENSE CONSIDERING THE CURRENT AMPLIFIED/BLOCKY PATTERN WE ARE NOW IN. THERE ARE TIMING DIFFERENCES...WITH THE ECMWF AND GFS IN MORE AGREEMENT...WITH THE TIMING/AMPLITUDE OF THE INDIVIDUAL WAVES. THE GFS IS FASTER AND LESS AMPLIFIED THAN THE ECMWF. NO MATTER WHAT THOUGH THIS PATTERN LEAVES THE AREA OPEN TO SHORTWAVES ROTATING THROUGH WITH SUBTROPICAL MOISTURE NEAR OR OVER THE AREA. THE ECMWF IS A LITTLE WETTER THAN THE GFS. SO DO LIKE WHAT THE CRH_INIT GAVE ME WITH THUNDERSTORM CHANCES EVERY DAY UNTIL SATURDAY WHEN IT LOOKS LIKE WE MAY DRY OUT. HOWEVER COULD SEE SATURDAY HAVING SOME LOW CHANCE OF THUNDERSTORMS. WILL LEAVE SATURDAY DRY FOR NOW SINCE IT IS A WEEK OUT PLUS THE MODELS ARE SHOWING ENOUGH DRYING TO SUPPORT THE DRY FORECAST. ALSO THIS PATTERN SUPPORTS THE CONTINUED HOT AND ABOVE NORMAL TEMPERATURES GIVEN TO ME BY THE INIT. THERE MAY BE A LITTLE COOL DOWN TOWARD THE END THOUGH. SO OVERALL PLAN ON LITTLE IF ANY CHANGES TO THE INIT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1107 PM MDT SAT AUG 16 2014 VFR CONDITIONS ARE EXPECTED OVERNIGHT AND SUNDAY AT KGLD AND KMCK. A DISTURBANCE MOVING INTO THE REGION WILL FIRE THUNDERSTORMS SUNDAY AFTERNOON WHICH MAY MOVE INTO THE KGLD AND KMCK AREAS WITH POSSIBLE BRIEF MVFR CONDITIONS. FORECAST SOUNDINGS INDICATE DECREASING CLOUDS BY LATE EVENING. NO VISIBILITY OR CIG REDUCTIONS FROM STRATUS/FOG ARE EXPECTED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1113 PM MDT SAT AUG 16 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 230 PM MDT SAT AUG 16 2014 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS 595 DM RIDGE CENTERED OVER SW US...WITH DIFFLUENT FLOW OVER THE NORTHERN PLAINS AHEAD OF A CLOSED LOW OVER THE SOUTHERN CANADIAN ROCKIES. AT THE SURFACE A COLD FRONT THAT MOVED INTO THE CWA LAST NIGHT ANS SHIFTED EAST WITH WEAK CONVERGENCE ALONG A TROUGH AXIS EXTENDING ACROSS EASTERN COLORADO. MODERATE INSTABILITY IS IN PLACE ACROSS THE EASTERN HALF OF THE CWA WITH ML CAPE VALUES IN THE 1000-2000 J/KG RANGE. LOWER VALUES AROUND 500 J/KG ARE IN PLACE ALONG THE TROUGH AXIS WHERE BETTER FOCUS FOR THUNDERSTORM INITIATION IS EXPECTED. HIGHER CINH WAS EXPECTED TO LIMIT INITIATION IN THE EAST...HOWEVER EXTENSIVE CU FIELD NOW IN PLACE WITH BETTER VERTICAL EXTENT THAT WOULD BE EXPECTED IF AIR MASS WAS COMPLETELY INHIBITED. WHERE THUNDERSTORMS HAVE DEVELOPED IN THE WEST WILL REMAIN MOST LIKELY AREA FOR CONVECTION ALONG WEAK CONVERGENCE ZONE...HOWEVER I COULDNT RULE OUT ISOLATED THUNDERSTORM ACTIVITY FURTHER EAST WERE CAP TO WEAKEN...ESPECIALLY WITH WESTERN EDGE OF FRONT NEAR OUR EASTERN CWA BORDER. HAVE EXTENDED AREA OF SLIGHT CHANCE POPS AND BUMPED UP COVERAGE IN THE SW. SEVERE THREAT REMAINS VERY LOW WITH WEAK SHEER...HOWEVER IF A BETTER UPDRAFT WERE TO DEVELOP IN THE EAST WHERE BETTER CAPE PROFILES EXIST THEN SEVERE HAIL/WIND COULD BE THREATS. BETTER THUNDERSTORM COVERAGE IS EXPECTED BY MID-LATE AFTERNOON SUNDAY AS A WEAK SHORTWAVE MOVES JUST NORTH OF THE CWA. MODELS HAVE A DECENT PRECIP SIGNAL OVER OUR CWA...DESPITE DRY SOUNDINGS...SO CHANCE POPS WERE RETAINED. THUNDERSTORMS WILL TEND TO BE ELEVATED..HOWEVER EFFECTIVE SHEER AROUND 35KT AND MODERATE MU CAPE IN THE 2000-2600 J/KG WOULD BE SUPPORTIVE OF A ELEVATED SEVERE WIND/HAIL THREAT WITH STORMS THAT DEVELOP. WIND MAY ACTUALLY BE THE GREATER THREAT CONSIDERING THE INVERTED V PROFILES IN PLACE. SOUTHERLY FLOW SHOULD BRING GOOD WAA BACK TO THE CWA...AND TEMPS SHOULD BE AS WARM IF NOT WARMER AS TODAY WITH VALUES IN THE MID- UPPER 90S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 230 PM MDT SAT AUG 16 2014 A PERSISTENT UPPER LEVEL PATTERN WILL REMAIN DRAPED ACROSS THE FORECAST AREA THROUGHOUT THE EXTENDED FORECAST PERIOD. THIS MEANS A CONTINUATION OF THE ABOVE NORMAL TEMPERATURES AND THUNDERSTORM CHANCES EACH AFTERNOON. FOR SUNDAY NIGHT...A STRONG SHORTWAVE WILL PROGRESS ACROSS THE NORTHERN GREAT PLAINS. SOME ENERGY SHOULD PASS OVER THE TRI-STATE REGION...LEADING SCATTERED THUNDERSTORMS. WITH THIS DISTURBANCE AND ASSOCIATED STRONGER WINDS MOVING THROUGH...THERE IS AN INCREASE IN WIND SHEAR. WITH ATMOSPHERE INSTABILITY/CAPE UP TO 2000-2500 J/KG...THERE COULD BE A MORE ORGANIZED THREAT FOR SEVERE WEATHER...ESPECIALLY EAST OF THE COLORADO BORDER. LARGE HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS AS BOUNDARY LAYER MOISTURE IS NOT SUPPORTIVE OF A TORNADIC ENVIRONMENT. MOST OF THE THUNDERSTORM ACTIVITY SHOULD LEAVE THE AREA BY MIDNIGHT AS THIS WILL BE A FAST MOVING SHORTWAVE. FOR MONDAY AFTERNOON/EVENING AND TUESDAY AFTERNOON/EVENING... ADDITIONAL UPPER DISTURBANCES LEAD TO CONTINUED CHANCES FOR STRONG/SEVERE THUNDERSTORMS. TUESDAY APPEARS HAVE A SLIGHTLY BETTER CHANCE OF CONVECTIVE ACTIVITY AS THERE ARE SOME QUESTIONS ABOUT ATMOSPHERE INSTABILITY MONDAY AND THE EFFECT THAT SUNDAY NIGHTS CONVECTION WOULD HAVE ON THE ENVIRONMENT. LARGE HAIL AND DAMAGING WINDS ARE ONCE AGAIN THE PRIMARY THREATS. FOR WEDNESDAY AND BEYOND...DISAGREEMENT WITHIN THE MODEL GUIDANCE LEADS TO LOWER CONFIDENCE IN THE TIMING AND LOCATIONS FOR BEST THUNDERSTORM CHANCES. THERE COULD BE STORMS EACH DAY WITH THE STAGNANT PATTERN AND CONTINUED UPPER LEVEL DISTURBANCE PASSAGES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1107 PM MDT SAT AUG 16 2014 VFR CONDITIONS ARE EXPECTED OVERNIGHT AND SUNDAY AT KGLD AND KMCK. A DISTURBANCE MOVING INTO THE REGION WILL FIRE THUNDERSTORMS SUNDAY AFTERNOON WHICH MAY MOVE INTO THE KGLD AND KMCK AREAS WITH POSSIBLE BRIEF MVFR CONDITIONS. FORECAST SOUNDINGS INDICATE DECREASING CLOUDS BY LATE EVENING. NO VISIBILITY OR CIG REDUCTIONS FROM STRATUS/FOG ARE EXPECTED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...RRH AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1130 PM EDT MON AUG 18 2014 .UPDATE... ISSUED AT 1130 PM EDT MON AUG 18 2014 UPDATED THE FORECAST TO ISSUE A DENSE FOG ADVISORY FOR EASTERN KENTUCKY. HAD REPORTS OF DENSE FOG MOST OF THE WAY FROM CLAY CITY TO JACKSON. AT SIGNS POINT TO A WIDESPREAD FOG EVENT TONIGHT THAT IS WORSE THAN THE NORMAL AUGUST VALLEY FOG. UPDATE ISSUED AT 702 PM EDT MON AUG 18 2014 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE PRECIPITATION HAS BEEN TAPERING OFF AS THE SHORT WAVE MOVES OFF TO THE EAST. LOWERED THE PROBABILITY OF PRECIPITATION BASED ON CURRENT RADAR AND THE LATEST HRRR OUTPUT. ALSO TOOK OUT THE CHANCE OF THUNDER OUT AS NONE HAS DEVELOPED ALL DAY AND THE MODELS ARE NOT SUPPORTING THEIR DEVELOPMENT IN THE NEAR TERM. THE ONLY THUNDER IS CURRENTLY OVER CENTRAL TENNESSEE. A WEAK FRONT IS STILL QUASI STATIONARY OVER THE AREA. EXPECT TO SEE SOME FAIRLY DENSE FOG TONIGHT...ESPECIALLY IN THE VALLEYS. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 255 PM EDT MON AUG 18 2014 THE LOW PRESSURE SYSTEM THAT BROUGHT THE WIDESPREAD RAIN LAST NIGHT INTO THIS MORNING HAS MOVED INTO WV...TAKING THE DEEPER MOISTURE AND BETTER LIFT WITH IT. A WEST EAST ORIENTED QUASI STATIONARY FRONT REMAINS ACROSS KENTUCKY...AND SCATTERED LIGHT SHOWERS CONTINUE TO MOVE FROM WEST TO EAST ACROSS THE AREA. ANOTHER WAVE OF LOW PRESSURE EVIDENT ON SATELLITE AND RADAR IMAGERY WAS MOVING EAST ALONG THE TN MS BORDER. THIS FEATURE...ALONG WITH THE BOUNDARY ACROSS KY WILL NECESSITATE CONTINUING WITH A CHANCE OF RAIN OVERNIGHT. HOWEVER THE BEST RAIN AND THUNDER CHANCES SHOULD BE SOUTH OF KY TONIGHT. WITH VERY MOIST BOUNDARY LAYER AND SOME BREAKS EXPECTED IN THE CLOUDS THIS EVENING...FOG AND LOW CLOUDS ARE EXPECTED TO DEVELOP DURING THE NIGHT AND LINGER INTO THE MORNING ON TUESDAY. WILL INCLUDE FOG IN THE FORECAST FOR TONIGHT. ON TUESDAY THE NEXT SHORT WAVE IN THIS VERY ACTIVE PATTERN WILL BE PUSHING INTO THE WESTERN GREAT LAKES REGION. AT THE SURFACE A VERY MOIST AND WARM AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KY ON TUESDAY...WHILE A COLD FRONT DROPS SOUTHEAST ACROSS IL AND INDIANA. THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THIS FRONT TUESDAY AFTERNOON. CURRENT THINKING IS THAT SHOWERS AND THUNDERSTORMS THAT DEVELOP TO OUR NORTHWEST ON TUESDAY WILL MOVE INTO OUR AREA TUESDAY NIGHT. WITH THIS THOUGHT IN MIND WILL INTRODUCE LIKELY PROBABILITIES FOR SHOWERS AND THUNDERSTORMS IN THE NORTHERN PART OF OUR FORECAST AREA TUESDAY NIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 255 PM EDT MON AUG 18 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED. UPPER/MID LEVEL GREAT LAKES LOW WILL MAKE A BEE LINE TO THE MID ATLANTIC COAST BY FRIDAY. MEANWHILE BURGEONING RIDGE TO OUR WEST WILL EXERT ITS INFLUENCE FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA NORTHWARD INTO THE UPPER MIDWEST. GREAT LAKES LOW WILL PASS TO OUR NORTHEAST DURING ITS MARCH TO THE COAST AND DRAG A SURFACE FRONTAL BOUNDARY ACROSS THE CENTER OF THE OHIO VALLEY REGION. SHARPENING UPPER LEVEL RIDGE AXIS WILL SHIFT SOUTHEASTWARD OVER OUR AREA TOWARDS THE END OF THE EXTENDED AS ENERGY ROUNDS ITS TOP ACROSS THE NORTHERN TIER. DESPITE THE BUILDING RIDGE ALOFT...THE BY THEN QUASI-STATIONARY SFC FRONTAL BOUNDARY WILL REMAIN IN OUR VICINITY AS IT BECOMES ORIENTED PARALLEL TO THE UPPER LEVEL FLOW PATTERN. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS...THIS BOUNDARY WILL REMAIN CLOSE ENOUGH TO OUR AREA TO SERVE AS A FOCUS FOR ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE LATTER HALF OF THE EXTENDED PERIOD. THE MAINLY DIURNAL SHOWER AND THUNDERSTORM ACTIVITY MAY BE AUGMENTED BY ONE OR TWO ORGANIZED THUNDERSTORM COMPLEXES DROPPING DOWN FROM THE NORTHWEST ON THE EAST SIDE OF THE UPPER RIDGE. FOR SENSIBLE WEATHER...WE WILL SEE THE RETURN OF TRUE SUMMER LIKE WEATHER AS RIDGING TO OUR SOUTHWEST WILL BE STRONG ENOUGH TO SEND TEMPERATURES INTO AND ABOVE SEASONABLE NORMS DESPITE THE INCREASED HUMIDITY. THIS WILL ALSO HELP TO ENHANCE THE DIURNALLY DRIVEN INSTABILITY ACROSS THE AREA RESULTING IN THE BEST CHANCES OF STORMS EACH AFTERNOON AND EVENING. THE THREAT OF RAIN DECREASES BY NEXT WEEKEND AS THE UPPER RIDGE AMPLIFIES AND SHIFTS EASTWARD A BIT...BUT THE POTENTIAL CAN NOT BE TOTALLY REMOVED. IN ADDITION...SHOULD THE RIDGE EXERT A STRONGER INFLUENCE BY SHIFTING JUST A BIT MORE EAST WE MAY BE IN FOR EVEN HOTTER WEATHER BY NEXT WEEKEND. WITH THE 0Z ECMWF ADVERTISING H850 TEMPS UP AROUND 22C TO 24C...THE POSSIBLY EXISTS THAT WE MIGHT SEE SOME OF OUR HOTTEST WEATHER OF THE SUMMER THUS FAR. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 702 PM EDT MON AUG 18 2014 A WIDE VARIETY OF CONDITIONS CAN BE EXPECTED ACROSS EASTERN KENTUCKY FOR THE REMAINDER OF THE EARLY EVENING. AS THERE IS SOME CLEARING THIS EVENING...EXPECT TO SEE SOME DENSE FOG FORMING IN THE VALLEYS AS WELL AS THE TAF STATIONS WITH VLIFR AND IFR CONDITIONS PREDOMINATING. THE FOG WILL MOST LIKELY TAKE UNTIL 14-15Z TO FINALLY BURN OFF. EXPECTING SOME SCATTERED SHOWERS AND THUNDERSTORMS TOMORROW ACROSS THE AREA. EXPECT THE ACTIVITY TO PICK UP IN THE LATE AFTERNOON AND EVENING. WILL MOST LIKELY NOT SEE MUCH VFR TOMORROW UNTIL THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM EDT TUESDAY FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JJ SHORT TERM...SBH LONG TERM...RAY AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
147 PM EDT SUN AUG 17 2014 .UPDATE... ISSUED AT 146 PM EDT SUN AUG 17 2014 LINE OF SHOWERS AND A FEW THUNDERSTORMS NOW OVER THE WESTERN PART OF THE FORECAST AREA CONTINUES TO MOVE EAST AND WEAKEN WITH TIME. THIS LINE WILL CONTINUE TO WEAKEN AS IT MOVES EAST THROUGH THE REMAINDER OF THE AFTERNOON. MAIN HEAVY RAIN THREAT STILL APPEARS TO BE LATER TONIGHT INTO EARLY MONDAY MORNING AS THE UPPER LEVEL LOW AND TROUGH PROGRESS EAST AND 8H LOW LEVEL JET RAMPS UP AND LIFT INCREASES. BASED ON 12Z SOUNDINGS AND SOME GOES SOUNDER DATA AVAILABLE BEFORE THE WIDESPREAD CLOUDS MOVED IN...PWS AROUND 2 INCHES SEEM REASONABLE AS FORECAST BY THE MAJORITY OF THE MODEL DATA FOR LATER TONIGHT. UPDATE ISSUED AT 939 AM EDT SUN AUG 17 2014 ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE AREA THIS MORNING...BUT ARE DIMINISHING. TOTAL LIGHTNING DATA IS SHOWING SOME IN CLOUD LIGHTNING WITH STORM OVER MENIFEE COUNTY. THIS HAS BEEN THE ONLY LIGHTNING NOTED IN OUR AREA THIS MORNING. FOCUS IS ON LARGE CONVECTIVE COMPLEX OVER WESTERN KY ASSOCIATED WITH THE MCV CENTERED OVER S IL/W KY. SATELLITE AND RADAR TRENDS HAVE SHOWN SOME OVERALL WEAKENING...HOWEVER NEW CONVECTION IS NOW DEVELOPING ON THE LEADING EDGE OF THIS SYSTEM...AND IT MAY SUSTAIN ITSELF INTO THE EARLY AFTERNOON. CURRENT MOVEMENT AND PROJECTED DEVELOPMENT ON THE LEADING EDGE WOULD BRING SHOWERS AND THUNDERSTORMS INTO THE WESTERN PART OF THE FORECAST AREA BETWEEN 11 AM AND NOON. ENVIRONMENT LOOKS LESS FAVORABLE FOR THIS CONVECTION TO MAINTAIN STRENGTH AS IT WILL MOVE EAST QUICKER THAN THE SUPPORTING UPPER TROUGH. THE LATEST HRRR DOES SHOW THE REMNANTS OF THE WESTERN KY CONVECTION MOVING ACROSS OUR AREA THIS AFTERNOON...BUT WEAKENING AS IT DOES SO. A QUICK LOOK AT THE 12Z SOUNDINGS SHOWS PW OF 1.32 AT ILN AND 1.83 AT OHX. BASED ON GOES SOUNDER DATA IT APPEARS THE OHX SOUNDING IS MORE REPRESENTATIVE OF THE AIR MASS OVER THE MAJORITY OF OUR AREA. AS THE TROUGH AXIS NOW OVER IL INTO SE MO MOVES EAST 8H WINDS OVER EASTERN KY WILL INCREASE THIS EVENING AND INTO THE NIGHT. THIS...COMBINED WITH HIGH PWS POINT TOWARDS THE BEST CHANCE FOR HEAVY RAIN FROM THIS EVENING INTO THE OVERNIGHT PERIOD. WILL UPDATE NDFD AND ASSOCIATED PRODUCTS SHORTLY AFTER 10 AM EDT TO ACCOUNT FOR LATEST OBSERVATIONAL TRENDS. UPDATE ISSUED AT 705 AM EDT SUN AUG 17 2014 CONDITIONS THIS MORNING ACROSS THE AREA FEATURE SOME SHOWERS NOW MOVING THROUGH THE AREA WITH A WEAKENED MCV UPSTREAM IN WESTERN KENTUCKY MAKING ITS WAY INTO CENTRAL KENTUCKY. THIS FEATURE WILL POSE A CONCERN FOR THE AREA TODAY AS IT SLOWLY TRACKS INTO EASTERN KENTUCKY BY THE AFTERNOON. THE ONE FORECAST CHALLENGE TODAY IS HOW FAVORABLE THE ENVIRONMENT WILL BE TO THIS FEATURE. MODEL SOUNDINGS...AS WELL AS THE HRRR DO NOT FAVOR INTENSIFYING THIS SYSTEM. SURFACE INSTABILITY WITH THE GFS IS RATHER LACKING AND THE HRRR SHOWS NO REAL INCREASE IN THE ECHOS. NONETHELESS...THE HEAVY RAIN THREAT MAY BEGIN SLIGHTLY EARLIER TODAY AS THE CURRENT SITUATION SEEMS TO JIVE WITH THE EXCESSIVE RAINFALL FORECAST. AS WELL...THE POSSIBILITY OF A STRONG STORM POSSESSING GUSTY WIND CAPABILITY INTO THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 330 AM EDT SUN AUG 17 2014 CURRENT CONDITIONS ACROSS THE AREA AS OF 07Z FEATURE SOME SHOWERS MOVING THROUGH EASTERN KENTUCKY FORMED BY SOME OVERRUNNING MOISTURE OVER A WEAK SURFACE WARM FRONT DEVELOPING AS A LOW PRESSURE CENTER OUT WEST CONTINUES TO DEVELOP AND SLOWLY MOVE EAST. A DRY LAYER AT THE SURFACE OVER MUCH OF THE AREA HAS HINDERED MEASURABLE PRECIP. HOWEVER...THIS BOUNDARY LAYER HAS AND WILL CONTINUE TO MOISTENED UP QUITE A BIT THROUGH THE PERIOD OF THE MORNING HOURS AS SOUTHERLY FLOW INCREASES AND RAINFALL FALLS OVER THESE AREAS. THIS RAINFALL ALONG WITH THE SURFACE BOUNDARY WILL WEAKEN AND LIFT OFF TO THE NORTHEAST AS THE LOW OUT WEST MOVES EAST. THIS WILL RESULT IN A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS AS THE BETTER FORCING AND MOISTURE MOVES EAST THIS AFTERNOON AND INTO THE EVENING. HEADING INTO THIS EVENING AND TONIGHT...THE SURFACE LOW BEGINS TO ENTER CENTRAL KY AND EVENTUALLY EASTERN KENTUCKY INTO MONDAY. MENTIONING THE FACT THAT THE MODELS HAVE NOT HANDLED THIS FEATURE WELL...ESPECIALLY THE NAM. MODEL SOUNDINGS FOR THE GFS AND NAM HAVE HAD SOLUTION PRETTY FAR APART WITH CONCERN WITH AVAILABLE MOISTURE WITH PWATS FOR THE NAM BEING WELL OVER 2.10 INCHES AND THE GFS BEING AROUND 1.70 INCHES. A SLIGHT RISK OF EXCESSIVE RAIN WAS ISSUED FOR THE AREA MAINLY ALONG THE I-75 CORRIDOR AND WEST FOR TONIGHT THROUGH MONDAY. THE FACT THAT THERE IS SO MUCH INCONSISTENCY IN THE MODELS...STORM MOTION IS ABOVE 10 KNOTS...AND FINALLY THE ADVERTISED WAVE LOOKS MUCH LESS POTENT THAN ADVERTISED...IT APPEARS THE RISK OF FLASH FLOODING WILL BE QUITE LOCALIZED AND ONLY CENTERED AROUND AREAS THAT ARE STILL DRYING OUT FROM LAST WEEK RAINS. ALSO AREAS WHERE STORMS MOVE REPEATEDLY OVER THE SAME AREA. AS SUCH...WILL ONLY CONTINUE MENTIONING THIS RISK IN THE HWO BASED UPON REASONING AS WELL AS COLLABORATION WITH SURROUNDING OFFICES. HOWEVER...THE WAVE AS WELL AS THE SURFACE FEATURE IS MOVING THROUGH QUITE SLOW SO THE CHANCE FOR STORMS TO MOVE OVER REPEATEDLY IS CERTAINLY A GOOD POSSIBILITY. THE CHALLENGING PORTION OF THE FORECAST WILL BE TONIGHT AND INTO MONDAY AND IDENTIFYING WHICH AREAS WILL RECEIVE HEAVY RAIN AND ALSO MONDAY AFTERNOON AS BASED UPON MODEL SOUNDINGS...A DRY LAYER DOES SHOW UP IN THE GFS IN CONJUNCTION WITH SOME GOOD INSTABILITY AND SHEAR. A MARGINAL SEVERE THREAT MAY ARISE. A CHALLENGING AND MURKY SHORT TERM FORECAST LOOKS TO BE THE CASE WITH A FEW CONCERNS. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 500 AM EDT SUN AUG 17 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED... INTERESTINGLY WITH THE GFS SHOWING A BIT MORE CONTINUITY THAN THE ECMWF THIS CYCLE. MID AND UPPER PATTERN WILL BE QUASI ZONAL AS A PROGRESSIVE BUT SLOW LOW AMPLITUDE WAVE MOVES ACROSS THE GREAT LAKES REGION. PATTERN AMPLIFIES A BIT TOWARDS THE END OF THE EXTENDED WINDOW WITH OUR FORECAST AREA ON THE EASTERN PERIPHERY OF RIDGE THAT EXTENDS FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA TO THE UPPER MIDWEST. AT THE SURFACE...LOW PRESSURE WILL BE EXITING TO OUR EAST JUST AS A SECOND LOW PRESSURE SYSTEM ROLLS THROUGH THE GREAT LAKES REGION BY MID WEEK. THE GREAT LAKES LOW WILL PULL A SURFACE COLD FRONTAL BOUNDARY ACROSS THE OHIO VALLEY. THIS FRONTAL BOUNDARY WILL BECOME ORIENTED IN A NORTHWEST TO SOUTHEAST DIRECTION...PARALLEL TO THE UPPER FLOW PATTERN ON THE EASTERN SIDE OF THE AFOREMENTIONED RIDGE. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS... THIS BOUNDARY WILL ESTABLISH A STATIONARY BAROCLINIC ZONE ACROSS THE REGION WHICH APPEARS TO SET UP JUST TO OUR NORTH AND EAST. IT APPEARS THIS ZONE WILL BECOME THE FOCUS OF ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY...AND SHOULD BE CLOSE ENOUGH THAT THE THREAT OF RAIN WILL CONTINUE TO EXIST FOR OUR AREA THROUGH THE REMAINDER OF THE FORECAST. MODELS EVEN HINT AT THE POSSIBILITY OF A SERIES OF MCS TYPE SYSTEMS DEVELOPING AND MOVING ALONG THIS ZONE...POSSIBLY AFFECTING PORTIONS OF OUR AREA. FOR SENSIBLE WEATHER...THE MOST SIGNIFICANT AND NOTABLE DIFFERENCE IN OUR WEATHER WILL BE THE RETURN OF TRUE SUMMER LIKE CONDITIONS WITH SEASONABLY WARM AND HUMID AFTERNOONS AND MUGGY NIGHTS. TWEAKED TEMPS TOWARDS LATEST MODEL BLENDS WHICH RESULTED IN ONLY MINOR CHANGES TO PREVIOUS FORECASTS. THE DAILY THREAT OF SOME TYPE OF SHOWER AND THUNDERSTORM ACTIVITY WILL ENSURE AN OVERALL UNSETTLED WEATHER PATTERN...ESPECIALLY IF CONDITIONS BECOME FAVORABLE FOR THE OCCASIONAL MCS SYSTEM TO MATERIALIZE AND MOVE THROUGH THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 146 PM EDT SUN AUG 17 2014 A BAND OF SHOWERS AND A FEW THUNDERSTORMS WILL WEAKEN AS IT MOVES EAST ACROSS THE FORECAST AREA THROUGH THE REMAINDER OF THE AFTERNOON. IN THE PRECIPITATION AREA MVFR TO IFR CONDITIONS CAN BE EXPECTED...WITH VFR PREVAILING OUTSIDE OF THE RAIN AREA. LOW PRESSURE OVER SOUTHERN INDIANA AND WESTERN KY WILL MOVE EAST TONIGHT BRINGING WIDESPREAD RAIN ALONG WITH SOME THUNDERSTORMS TO THE AREA. CONDITIONS WILL DETERIORATE AFTER 03Z WITH WIDESPREAD MVFR TO IFR CONDITIONS EXPECTED FOR LATE TONIGHT INTO MONDAY MORNING. CONDITIONS WILL BE SLOW TO IMPROVE ON MONDAY. THE RAIN AND THUNDERSTORMS WILL END FROM WEST TO EAST DURING THE MORNING BUT LOW CLOUD AND FOG WILL LINGER AFTER THE RAIN ENDS. VFR CONDITIONS ARE EXPECTED TO RETURN MONDAY AFTERNOON. WINDS WILL REMAIN LIGHT THROUGH THE FORECAST PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...SHALLENBERGER LONG TERM...RAY AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
939 AM EDT SUN AUG 17 2014 .UPDATE... ISSUED AT 939 AM EDT SUN AUG 17 2014 ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE AREA THIS MORNING...BUT ARE DIMINISHING. TOTAL LIGHTNING DATA IS SHOWING SOME IN CLOUD LIGHTNING WITH STORM OVER MENIFEE COUNTY. THIS HAS BEEN THE ONLY LIGHTNING NOTED IN OUR AREA THIS MORNING. FOCUS IS ON LARGE CONVECTIVE COMPLEX OVER WESTERN KY ASSOCIATED WITH THE MCV CENTERED OVER S IL/W KY. SATELLITE AND RADAR TRENDS HAVE SHOWN SOME OVERALL WEAKENING...HOWEVER NEW CONVECTION IS NOW DEVELOPING ON THE LEADING EDGE OF THIS SYSTEM...AND IT MAY SUSTAIN ITSELF INTO THE EARLY AFTERNOON. CURRENT MOVEMENT AND PROJECTED DEVELOPMENT ON THE LEADING EDGE WOULD BRING SHOWERS AND THUNDERSTORMS INTO THE WESTERN PART OF THE FORECAST AREA BETWEEN 11 AM AND NOON. ENVIRONMENT LOOKS LESS FAVORABLE FOR THIS CONVECTION TO MAINTAIN STRENGTH AS IT WILL MOVE EAST QUICKER THAN THE SUPPORTING UPPER TROUGH. THE LATEST HRRR DOES SHOW THE REMNANTS OF THE WESTERN KY CONVECTION MOVING ACROSS OUR AREA THIS AFTERNOON...BUT WEAKENING AS IT DOES SO. A QUICK LOOK AT THE 12Z SOUNDINGS SHOWS PW OF 1.32 AT ILN AND 1.83 AT OHX. BASED ON GOES SOUNDER DATA IT APPEARS THE OHX SOUNDING IS MORE REPRESENTATIVE OF THE AIR MASS OVER THE MAJORITY OF OUR AREA. AS THE TROUGH AXIS NOW OVER IL INTO SE MO MOVES EAST 8H WINDS OVER EASTERN KY WILL INCREASE THIS EVENING AND INTO THE NIGHT. THIS...COMBINED WITH HIGH PWS POINT TOWARDS THE BEST CHANCE FOR HEAVY RAIN FROM THIS EVENING INTO THE OVERNIGHT PERIOD. WILL UPDATE NDFD AND ASSOCIATED PRODUCTS SHORTLY AFTER 10 AM EDT TO ACCOUNT FOR LATEST OBSERVATIONAL TRENDS. UPDATE ISSUED AT 705 AM EDT SUN AUG 17 2014 CONDITIONS THIS MORNING ACROSS THE AREA FEATURE SOME SHOWERS NOW MOVING THROUGH THE AREA WITH A WEAKENED MCV UPSTREAM IN WESTERN KENTUCKY MAKING ITS WAY INTO CENTRAL KENTUCKY. THIS FEATURE WILL POSE A CONCERN FOR THE AREA TODAY AS IT SLOWLY TRACKS INTO EASTERN KENTUCKY BY THE AFTERNOON. THE ONE FORECAST CHALLENGE TODAY IS HOW FAVORABLE THE ENVIRONMENT WILL BE TO THIS FEATURE. MODEL SOUNDINGS...AS WELL AS THE HRRR DO NOT FAVOR INTENSIFYING THIS SYSTEM. SURFACE INSTABILITY WITH THE GFS IS RATHER LACKING AND THE HRRR SHOWS NO REAL INCREASE IN THE ECHOS. NONETHELESS...THE HEAVY RAIN THREAT MAY BEGIN SLIGHTLY EARLIER TODAY AS THE CURRENT SITUATION SEEMS TO JIVE WITH THE EXCESSIVE RAINFALL FORECAST. AS WELL...THE POSSIBILITY OF A STRONG STORM POSSESSING GUSTY WIND CAPABILITY INTO THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 330 AM EDT SUN AUG 17 2014 CURRENT CONDITIONS ACROSS THE AREA AS OF 07Z FEATURE SOME SHOWERS MOVING THROUGH EASTERN KENTUCKY FORMED BY SOME OVERRUNNING MOISTURE OVER A WEAK SURFACE WARM FRONT DEVELOPING AS A LOW PRESSURE CENTER OUT WEST CONTINUES TO DEVELOP AND SLOWLY MOVE EAST. A DRY LAYER AT THE SURFACE OVER MUCH OF THE AREA HAS HINDERED MEASURABLE PRECIP. HOWEVER...THIS BOUNDARY LAYER HAS AND WILL CONTINUE TO MOISTENED UP QUITE A BIT THROUGH THE PERIOD OF THE MORNING HOURS AS SOUTHERLY FLOW INCREASES AND RAINFALL FALLS OVER THESE AREAS. THIS RAINFALL ALONG WITH THE SURFACE BOUNDARY WILL WEAKEN AND LIFT OFF TO THE NORTHEAST AS THE LOW OUT WEST MOVES EAST. THIS WILL RESULT IN A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS AS THE BETTER FORCING AND MOISTURE MOVES EAST THIS AFTERNOON AND INTO THE EVENING. HEADING INTO THIS EVENING AND TONIGHT...THE SURFACE LOW BEGINS TO ENTER CENTRAL KY AND EVENTUALLY EASTERN KENTUCKY INTO MONDAY. MENTIONING THE FACT THAT THE MODELS HAVE NOT HANDLED THIS FEATURE WELL...ESPECIALLY THE NAM. MODEL SOUNDINGS FOR THE GFS AND NAM HAVE HAD SOLUTION PRETTY FAR APART WITH CONCERN WITH AVAILABLE MOISTURE WITH PWATS FOR THE NAM BEING WELL OVER 2.10 INCHES AND THE GFS BEING AROUND 1.70 INCHES. A SLIGHT RISK OF EXCESSIVE RAIN WAS ISSUED FOR THE AREA MAINLY ALONG THE I-75 CORRIDOR AND WEST FOR TONIGHT THROUGH MONDAY. THE FACT THAT THERE IS SO MUCH INCONSISTENCY IN THE MODELS...STORM MOTION IS ABOVE 10 KNOTS...AND FINALLY THE ADVERTISED WAVE LOOKS MUCH LESS POTENT THAN ADVERTISED...IT APPEARS THE RISK OF FLASH FLOODING WILL BE QUITE LOCALIZED AND ONLY CENTERED AROUND AREAS THAT ARE STILL DRYING OUT FROM LAST WEEK RAINS. ALSO AREAS WHERE STORMS MOVE REPEATEDLY OVER THE SAME AREA. AS SUCH...WILL ONLY CONTINUE MENTIONING THIS RISK IN THE HWO BASED UPON REASONING AS WELL AS COLLABORATION WITH SURROUNDING OFFICES. HOWEVER...THE WAVE AS WELL AS THE SURFACE FEATURE IS MOVING THROUGH QUITE SLOW SO THE CHANCE FOR STORMS TO MOVE OVER REPEATEDLY IS CERTAINLY A GOOD POSSIBILITY. THE CHALLENGING PORTION OF THE FORECAST WILL BE TONIGHT AND INTO MONDAY AND IDENTIFYING WHICH AREAS WILL RECEIVE HEAVY RAIN AND ALSO MONDAY AFTERNOON AS BASED UPON MODEL SOUNDINGS...A DRY LAYER DOES SHOW UP IN THE GFS IN CONJUNCTION WITH SOME GOOD INSTABILITY AND SHEAR. A MARGINAL SEVERE THREAT MAY ARISE. A CHALLENGING AND MURKY SHORT TERM FORECAST LOOKS TO BE THE CASE WITH A FEW CONCERNS. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 500 AM EDT SUN AUG 17 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED... INTERESTINGLY WITH THE GFS SHOWING A BIT MORE CONTINUITY THAN THE ECMWF THIS CYCLE. MID AND UPPER PATTERN WILL BE QUASI ZONAL AS A PROGRESSIVE BUT SLOW LOW AMPLITUDE WAVE MOVES ACROSS THE GREAT LAKES REGION. PATTERN AMPLIFIES A BIT TOWARDS THE END OF THE EXTENDED WINDOW WITH OUR FORECAST AREA ON THE EASTERN PERIPHERY OF RIDGE THAT EXTENDS FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA TO THE UPPER MIDWEST. AT THE SURFACE...LOW PRESSURE WILL BE EXITING TO OUR EAST JUST AS A SECOND LOW PRESSURE SYSTEM ROLLS THROUGH THE GREAT LAKES REGION BY MID WEEK. THE GREAT LAKES LOW WILL PULL A SURFACE COLD FRONTAL BOUNDARY ACROSS THE OHIO VALLEY. THIS FRONTAL BOUNDARY WILL BECOME ORIENTED IN A NORTHWEST TO SOUTHEAST DIRECTION...PARALLEL TO THE UPPER FLOW PATTERN ON THE EASTERN SIDE OF THE AFOREMENTIONED RIDGE. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS... THIS BOUNDARY WILL ESTABLISH A STATIONARY BAROCLINIC ZONE ACROSS THE REGION WHICH APPEARS TO SET UP JUST TO OUR NORTH AND EAST. IT APPEARS THIS ZONE WILL BECOME THE FOCUS OF ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY...AND SHOULD BE CLOSE ENOUGH THAT THE THREAT OF RAIN WILL CONTINUE TO EXIST FOR OUR AREA THROUGH THE REMAINDER OF THE FORECAST. MODELS EVEN HINT AT THE POSSIBILITY OF A SERIES OF MCS TYPE SYSTEMS DEVELOPING AND MOVING ALONG THIS ZONE...POSSIBLY AFFECTING PORTIONS OF OUR AREA. FOR SENSIBLE WEATHER...THE MOST SIGNIFICANT AND NOTABLE DIFFERENCE IN OUR WEATHER WILL BE THE RETURN OF TRUE SUMMER LIKE CONDITIONS WITH SEASONABLY WARM AND HUMID AFTERNOONS AND MUGGY NIGHTS. TWEAKED TEMPS TOWARDS LATEST MODEL BLENDS WHICH RESULTED IN ONLY MINOR CHANGES TO PREVIOUS FORECASTS. THE DAILY THREAT OF SOME TYPE OF SHOWER AND THUNDERSTORM ACTIVITY WILL ENSURE AN OVERALL UNSETTLED WEATHER PATTERN...ESPECIALLY IF CONDITIONS BECOME FAVORABLE FOR THE OCCASIONAL MCS SYSTEM TO MATERIALIZE AND MOVE THROUGH THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 735 AM EDT SUN AUG 17 2014 A BAND OF LIGHT RAIN SHOWERS ACROSS THE HEART OF THE FORECAST AREA ALONG WITH A SMALL AREA OF RAIN IN THE SOUTH APPEAR TO BE WEAKENING WITH TIME. HOWEVER...UPSTREAM STORM SYSTEM IS POISED TO MAKE A RUN AT OUR AREA LATER TODAY. FOLLOWED VERY NEAR TERM...HIGHER RESOLUTION MODELS CLOSELY WITH RESPECT TO TIMING SHOWER AND THUNDERSTORM ACTIVITY INTO AND OUT OF THE AREA...BUT CONFIDENCE IS LOW. THAT BEING SAID CURRENT ACTIVITY SHOULD CONTINUE TO WEAKEN OVER THE NEXT COUPLE OF HOURS. THEN EXPECT AN EARLY TO MID MORNING LULL BEFORE ACTIVITY PICKS BACK UP TOWARDS NOON AND CONTINUES THROUGH THE REMAINDER OF THE FORECAST. THREAT OF THUNDERSTORMS WILL INCREASE WITH TIME AS WELL. IN GENERAL WENT WITH VRF CONDITIONS UNTIL THIS EVENING/TONIGHT AS VSBYS AND CIGS EVENTUALLY RESPOND TO THE RAINFALL AND AN INCREASINGLY SATURATED BOUNDARY LAYER. WINDS WILL BE LIGHT AND ROUGHLY SOUTHERLY AT ABOUT 5 KTS OR LESS THROUGH THE ENTIRE FORECAST PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...SHALLENBERGER LONG TERM...RAY AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
735 AM EDT SUN AUG 17 2014 .UPDATE... ISSUED AT 705 AM EDT SUN AUG 17 2014 CONDITIONS THIS MORNING ACROSS THE AREA FEATURE SOME SHOWERS NOW MOVING THROUGH THE AREA WITH A WEAKENED MCV UPSTREAM IN WESTERN KENTUCKY MAKING ITS WAY INTO CENTRAL KENTUCKY. THIS FEATURE WILL POSE A CONCERN FOR THE AREA TODAY AS IT SLOWLY TRACKS INTO EASTERN KENTUCKY BY THE AFTERNOON. THE ONE FORECAST CHALLENGE TODAY IS HOW FAVORABLE THE ENVIRONMENT WILL BE TO THIS FEATURE. MODEL SOUNDINGS...AS WELL AS THE HRRR DO NOT FAVOR INTENSIFYING THIS SYSTEM. SURFACE INSTABILITY WITH THE GFS IS RATHER LACKING AND THE HRRR SHOWS NO REAL INCREASE IN THE ECHOS. NONETHELESS...THE HEAVY RAIN THREAT MAY BEGIN SLIGHTLY EARLIER TODAY AS THE CURRENT SITUATION SEEMS TO JIVE WITH THE EXCESSIVE RAINFALL FORECAST. AS WELL...THE POSSIBILITY OF A STRONG STORM POSSESSING GUSTY WIND CAPABILITY INTO THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 330 AM EDT SUN AUG 17 2014 CURRENT CONDITIONS ACROSS THE AREA AS OF 07Z FEATURE SOME SHOWERS MOVING THROUGH EASTERN KENTUCKY FORMED BY SOME OVERRUNNING MOISTURE OVER A WEAK SURFACE WARM FRONT DEVELOPING AS A LOW PRESSURE CENTER OUT WEST CONTINUES TO DEVELOP AND SLOWLY MOVE EAST. A DRY LAYER AT THE SURFACE OVER MUCH OF THE AREA HAS HINDERED MEASURABLE PRECIP. HOWEVER...THIS BOUNDARY LAYER HAS AND WILL CONTINUE TO MOISTENED UP QUITE A BIT THROUGH THE PERIOD OF THE MORNING HOURS AS SOUTHERLY FLOW INCREASES AND RAINFALL FALLS OVER THESE AREAS. THIS RAINFALL ALONG WITH THE SURFACE BOUNDARY WILL WEAKEN AND LIFT OFF TO THE NORTHEAST AS THE LOW OUT WEST MOVES EAST. THIS WILL RESULT IN A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS AS THE BETTER FORCING AND MOISTURE MOVES EAST THIS AFTERNOON AND INTO THE EVENING. HEADING INTO THIS EVENING AND TONIGHT...THE SURFACE LOW BEGINS TO ENTER CENTRAL KY AND EVENTUALLY EASTERN KENTUCKY INTO MONDAY. MENTIONING THE FACT THAT THE MODELS HAVE NOT HANDLED THIS FEATURE WELL...ESPECIALLY THE NAM. MODEL SOUNDINGS FOR THE GFS AND NAM HAVE HAD SOLUTION PRETTY FAR APART WITH CONCERN WITH AVAILABLE MOISTURE WITH PWATS FOR THE NAM BEING WELL OVER 2.10 INCHES AND THE GFS BEING AROUND 1.70 INCHES. A SLIGHT RISK OF EXCESSIVE RAIN WAS ISSUED FOR THE AREA MAINLY ALONG THE I-75 CORRIDOR AND WEST FOR TONIGHT THROUGH MONDAY. THE FACT THAT THERE IS SO MUCH INCONSISTENCY IN THE MODELS...STORM MOTION IS ABOVE 10 KNOTS...AND FINALLY THE ADVERTISED WAVE LOOKS MUCH LESS POTENT THAN ADVERTISED...IT APPEARS THE RISK OF FLASH FLOODING WILL BE QUITE LOCALIZED AND ONLY CENTERED AROUND AREAS THAT ARE STILL DRYING OUT FROM LAST WEEK RAINS. ALSO AREAS WHERE STORMS MOVE REPEATEDLY OVER THE SAME AREA. AS SUCH...WILL ONLY CONTINUE MENTIONING THIS RISK IN THE HWO BASED UPON REASONING AS WELL AS COLLABORATION WITH SURROUNDING OFFICES. HOWEVER...THE WAVE AS WELL AS THE SURFACE FEATURE IS MOVING THROUGH QUITE SLOW SO THE CHANCE FOR STORMS TO MOVE OVER REPEATEDLY IS CERTAINLY A GOOD POSSIBILITY. THE CHALLENGING PORTION OF THE FORECAST WILL BE TONIGHT AND INTO MONDAY AND IDENTIFYING WHICH AREAS WILL RECEIVE HEAVY RAIN AND ALSO MONDAY AFTERNOON AS BASED UPON MODEL SOUNDINGS...A DRY LAYER DOES SHOW UP IN THE GFS IN CONJUNCTION WITH SOME GOOD INSTABILITY AND SHEAR. A MARGINAL SEVERE THREAT MAY ARISE. A CHALLENGING AND MURKY SHORT TERM FORECAST LOOKS TO BE THE CASE WITH A FEW CONCERNS. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 500 AM EDT SUN AUG 17 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED... INTERESTINGLY WITH THE GFS SHOWING A BIT MORE CONTINUITY THAN THE ECMWF THIS CYCLE. MID AND UPPER PATTERN WILL BE QUASI ZONAL AS A PROGRESSIVE BUT SLOW LOW AMPLITUDE WAVE MOVES ACROSS THE GREAT LAKES REGION. PATTERN AMPLIFIES A BIT TOWARDS THE END OF THE EXTENDED WINDOW WITH OUR FORECAST AREA ON THE EASTERN PERIPHERY OF RIDGE THAT EXTENDS FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA TO THE UPPER MIDWEST. AT THE SURFACE...LOW PRESSURE WILL BE EXITING TO OUR EAST JUST AS A SECOND LOW PRESSURE SYSTEM ROLLS THROUGH THE GREAT LAKES REGION BY MID WEEK. THE GREAT LAKES LOW WILL PULL A SURFACE COLD FRONTAL BOUNDARY ACROSS THE OHIO VALLEY. THIS FRONTAL BOUNDARY WILL BECOME ORIENTED IN A NORTHWEST TO SOUTHEAST DIRECTION...PARALLEL TO THE UPPER FLOW PATTERN ON THE EASTERN SIDE OF THE AFOREMENTIONED RIDGE. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS... THIS BOUNDARY WILL ESTABLISH A STATIONARY BAROCLINIC ZONE ACROSS THE REGION WHICH APPEARS TO SET UP JUST TO OUR NORTH AND EAST. IT APPEARS THIS ZONE WILL BECOME THE FOCUS OF ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY...AND SHOULD BE CLOSE ENOUGH THAT THE THREAT OF RAIN WILL CONTINUE TO EXIST FOR OUR AREA THROUGH THE REMAINDER OF THE FORECAST. MODELS EVEN HINT AT THE POSSIBILITY OF A SERIES OF MCS TYPE SYSTEMS DEVELOPING AND MOVING ALONG THIS ZONE...POSSIBLY AFFECTING PORTIONS OF OUR AREA. FOR SENSIBLE WEATHER...THE MOST SIGNIFICANT AND NOTABLE DIFFERENCE IN OUR WEATHER WILL BE THE RETURN OF TRUE SUMMER LIKE CONDITIONS WITH SEASONABLY WARM AND HUMID AFTERNOONS AND MUGGY NIGHTS. TWEAKED TEMPS TOWARDS LATEST MODEL BLENDS WHICH RESULTED IN ONLY MINOR CHANGES TO PREVIOUS FORECASTS. THE DAILY THREAT OF SOME TYPE OF SHOWER AND THUNDERSTORM ACTIVITY WILL ENSURE AN OVERALL UNSETTLED WEATHER PATTERN...ESPECIALLY IF CONDITIONS BECOME FAVORABLE FOR THE OCCASIONAL MCS SYSTEM TO MATERIALIZE AND MOVE THROUGH THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 735 AM EDT SUN AUG 17 2014 A BAND OF LIGHT RAIN SHOWERS ACROSS THE HEART OF THE FORECAST AREA ALONG WITH A SMALL AREA OF RAIN IN THE SOUTH APPEAR TO BE WEAKENING WITH TIME. HOWEVER...UPSTREAM STORM SYSTEM IS POISED TO MAKE A RUN AT OUR AREA LATER TODAY. FOLLOWED VERY NEAR TERM...HIGHER RESOLUTION MODELS CLOSELY WITH RESPECT TO TIMING SHOWER AND THUNDERSTORM ACTIVITY INTO AND OUT OF THE AREA...BUT CONFIDENCE IS LOW. THAT BEING SAID CURRENT ACTIVITY SHOULD CONTINUE TO WEAKEN OVER THE NEXT COUPLE OF HOURS. THEN EXPECT AN EARLY TO MID MORNING LULL BEFORE ACTIVITY PICKS BACK UP TOWARDS NOON AND CONTINUES THROUGH THE REMAINDER OF THE FORECAST. THREAT OF THUNDERSTORMS WILL INCREASE WITH TIME AS WELL. IN GENERAL WENT WITH VRF CONDITIONS UNTIL THIS EVENING/TONIGHT AS VSBYS AND CIGS EVENTUALLY RESPOND TO THE RAINFALL AND AN INCREASINGLY SATURATED BOUNDARY LAYER. WINDS WILL BE LIGHT AND ROUGHLY SOUTHERLY AT ABOUT 5 KTS OR LESS THROUGH THE ENTIRE FORECAST PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...SHALLENBERGER LONG TERM...RAY AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
705 AM EDT SUN AUG 17 2014 .UPDATE... ISSUED AT 705 AM EDT SUN AUG 17 2014 CONDITIONS THIS MORNING ACROSS THE AREA FEATURE SOME SHOWERS NOW MOVING THROUGH THE AREA WITH A WEAKENED MCV UPSTREAM IN WESTERN KENTUCKY MAKING ITS WAY INTO CENTRAL KENTUCKY. THIS FEATURE WILL POSE A CONCERN FOR THE AREA TODAY AS IT SLOWLY TRACKS INTO EASTERN KENTUCKY BY THE AFTERNOON. THE ONE FORECAST CHALLENGE TODAY IS HOW FAVORABLE THE ENVIRONMENT WILL BE TO THIS FEATURE. MODEL SOUNDINGS...AS WELL AS THE HRRR DO NOT FAVOR INTENSIFYING THIS SYSTEM. SURFACE INSTABILITY WITH THE GFS IS RATHER LACKING AND THE HRRR SHOWS NO REAL INCREASE IN THE ECHOS. NONETHELESS...THE HEAVY RAIN THREAT MAY BEGIN SLIGHTLY EARLIER TODAY AS THE CURRENT SITUATION SEEMS TO JIVE WITH THE EXCESSIVE RAINFALL FORECAST. AS WELL...THE POSSIBILITY OF A STRONG STORM POSSESSING GUSTY WIND CAPABILITY INTO THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 330 AM EDT SUN AUG 17 2014 CURRENT CONDITIONS ACROSS THE AREA AS OF 07Z FEATURE SOME SHOWERS MOVING THROUGH EASTERN KENTUCKY FORMED BY SOME OVERRUNNING MOISTURE OVER A WEAK SURFACE WARM FRONT DEVELOPING AS A LOW PRESSURE CENTER OUT WEST CONTINUES TO DEVELOP AND SLOWLY MOVE EAST. A DRY LAYER AT THE SURFACE OVER MUCH OF THE AREA HAS HINDERED MEASURABLE PRECIP. HOWEVER...THIS BOUNDARY LAYER HAS AND WILL CONTINUE TO MOISTENED UP QUITE A BIT THROUGH THE PERIOD OF THE MORNING HOURS AS SOUTHERLY FLOW INCREASES AND RAINFALL FALLS OVER THESE AREAS. THIS RAINFALL ALONG WITH THE SURFACE BOUNDARY WILL WEAKEN AND LIFT OFF TO THE NORTHEAST AS THE LOW OUT WEST MOVES EAST. THIS WILL RESULT IN A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS AS THE BETTER FORCING AND MOISTURE MOVES EAST THIS AFTERNOON AND INTO THE EVENING. HEADING INTO THIS EVENING AND TONIGHT...THE SURFACE LOW BEGINS TO ENTER CENTRAL KY AND EVENTUALLY EASTERN KENTUCKY INTO MONDAY. MENTIONING THE FACT THAT THE MODELS HAVE NOT HANDLED THIS FEATURE WELL...ESPECIALLY THE NAM. MODEL SOUNDINGS FOR THE GFS AND NAM HAVE HAD SOLUTION PRETTY FAR APART WITH CONCERN WITH AVAILABLE MOISTURE WITH PWATS FOR THE NAM BEING WELL OVER 2.10 INCHES AND THE GFS BEING AROUND 1.70 INCHES. A SLIGHT RISK OF EXCESSIVE RAIN WAS ISSUED FOR THE AREA MAINLY ALONG THE I-75 CORRIDOR AND WEST FOR TONIGHT THROUGH MONDAY. THE FACT THAT THERE IS SO MUCH INCONSISTENCY IN THE MODELS...STORM MOTION IS ABOVE 10 KNOTS...AND FINALLY THE ADVERTISED WAVE LOOKS MUCH LESS POTENT THAN ADVERTISED...IT APPEARS THE RISK OF FLASH FLOODING WILL BE QUITE LOCALIZED AND ONLY CENTERED AROUND AREAS THAT ARE STILL DRYING OUT FROM LAST WEEK RAINS. ALSO AREAS WHERE STORMS MOVE REPEATEDLY OVER THE SAME AREA. AS SUCH...WILL ONLY CONTINUE MENTIONING THIS RISK IN THE HWO BASED UPON REASONING AS WELL AS COLLABORATION WITH SURROUNDING OFFICES. HOWEVER...THE WAVE AS WELL AS THE SURFACE FEATURE IS MOVING THROUGH QUITE SLOW SO THE CHANCE FOR STORMS TO MOVE OVER REPEATEDLY IS CERTAINLY A GOOD POSSIBILITY. THE CHALLENGING PORTION OF THE FORECAST WILL BE TONIGHT AND INTO MONDAY AND IDENTIFYING WHICH AREAS WILL RECEIVE HEAVY RAIN AND ALSO MONDAY AFTERNOON AS BASED UPON MODEL SOUNDINGS...A DRY LAYER DOES SHOW UP IN THE GFS IN CONJUNCTION WITH SOME GOOD INSTABILITY AND SHEAR. A MARGINAL SEVERE THREAT MAY ARISE. A CHALLENGING AND MURKY SHORT TERM FORECAST LOOKS TO BE THE CASE WITH A FEW CONCERNS. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 500 AM EDT SUN AUG 17 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED... INTERESTINGLY WITH THE GFS SHOWING A BIT MORE CONTINUITY THAN THE ECMWF THIS CYCLE. MID AND UPPER PATTERN WILL BE QUASI ZONAL AS A PROGRESSIVE BUT SLOW LOW AMPLITUDE WAVE MOVES ACROSS THE GREAT LAKES REGION. PATTERN AMPLIFIES A BIT TOWARDS THE END OF THE EXTENDED WINDOW WITH OUR FORECAST AREA ON THE EASTERN PERIPHERY OF RIDGE THAT EXTENDS FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA TO THE UPPER MIDWEST. AT THE SURFACE...LOW PRESSURE WILL BE EXITING TO OUR EAST JUST AS A SECOND LOW PRESSURE SYSTEM ROLLS THROUGH THE GREAT LAKES REGION BY MID WEEK. THE GREAT LAKES LOW WILL PULL A SURFACE COLD FRONTAL BOUNDARY ACROSS THE OHIO VALLEY. THIS FRONTAL BOUNDARY WILL BECOME ORIENTED IN A NORTHWEST TO SOUTHEAST DIRECTION...PARALLEL TO THE UPPER FLOW PATTERN ON THE EASTERN SIDE OF THE AFOREMENTIONED RIDGE. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS... THIS BOUNDARY WILL ESTABLISH A STATIONARY BAROCLINIC ZONE ACROSS THE REGION WHICH APPEARS TO SET UP JUST TO OUR NORTH AND EAST. IT APPEARS THIS ZONE WILL BECOME THE FOCUS OF ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY...AND SHOULD BE CLOSE ENOUGH THAT THE THREAT OF RAIN WILL CONTINUE TO EXIST FOR OUR AREA THROUGH THE REMAINDER OF THE FORECAST. MODELS EVEN HINT AT THE POSSIBILITY OF A SERIES OF MCS TYPE SYSTEMS DEVELOPING AND MOVING ALONG THIS ZONE...POSSIBLY AFFECTING PORTIONS OF OUR AREA. FOR SENSIBLE WEATHER...THE MOST SIGNIFICANT AND NOTABLE DIFFERENCE IN OUR WEATHER WILL BE THE RETURN OF TRUE SUMMER LIKE CONDITIONS WITH SEASONABLY WARM AND HUMID AFTERNOONS AND MUGGY NIGHTS. TWEAKED TEMPS TOWARDS LATEST MODEL BLENDS WHICH RESULTED IN ONLY MINOR CHANGES TO PREVIOUS FORECASTS. THE DAILY THREAT OF SOME TYPE OF SHOWER AND THUNDERSTORM ACTIVITY WILL ENSURE AN OVERALL UNSETTLED WEATHER PATTERN...ESPECIALLY IF CONDITIONS BECOME FAVORABLE FOR THE OCCASIONAL MCS SYSTEM TO MATERIALIZE AND MOVE THROUGH THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 134 AM EDT SUN AUG 17 2014 EXPECT SOME MID LEVEL CLOUDS TO REMAIN OVER THE AREA AS SOME SHOWERS AND EXTENSIVE CLOUD COVER AHEAD OF AN APPROACHING WARM FRONT MOVING INTO THE AREA. THOUGH FOR NOW...LOW CEILINGS OR LOW VISIBILITY SHOULD NOT BE AN ISSUE WITH THE EXCEPTION OF A FEW OF THE DEEPER VALLEYS ACROSS EASTERN KENTUCKY. AS THE APPROACHING SYSTEM DEVELOPS...SHOWERS WILL BECOME MORE NUMEROUS ALONG WITH SCATTERED THUNDERSTORMS BY THIS AFTERNOON AND INTO THE EVENING. MOST SITES WILL BEGIN TO GO DOWN WITH LOW CEILINGS AND LOW VISIBILITY BY 00Z. WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD WITH THE EXCEPTION OF A THUNDERSTORM MOVING OVER A STATION. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...SHALLENBERGER LONG TERM...RAY AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
101 PM CDT SUN AUG 17 2014 .AVIATION... FOR THE 17/18Z TAFS...A MIX OF MVFR/LOW END VFR CONDITIONS WILL LIKELY PREVAIL FOR MUCH OF THE PERIOD AT LOCATIONS THAT ARE NOT EXPERIENCING RAIN. LARGE AREA OF RAIN ASSOCIATED WITH A SLOW MOVING MID LVL TROUGH HAS MADE VERY LITTLE PROGRESS EWD OVER THE LAST FEW HRS WHILE ALSO SHOWING A DECREASE IN INTENSITY PER LATEST RADAR LOOPS. THIS UPPER TROUGH SHOULD EVENTUALLY MOVE FARTHER EAST INTO THE AREA. CONVECTION SHOULD REDEVELOP/RE-INTENSIFY DURING THE LATE AFTERNOON AND INTO THE EVENING HRS. SCT SHWRS/TSTMS LIKELY TO PERSIST THROUGH THE NIGHT AND INTO EARLY MONDAY MORNING AS THE SYSTEM CONTINUES TO SLOWLY MOVE EWD. FARTHER SOUTH...SEA BREEZE CONVECTION HAS STARTED TO EXPAND IN COVERAGE BUT WILL MAINLY BE CONFINED SOUTH OF I-20. HAVE INCLUDED VCTS AT KLFK TO ACCOUNT FOR THIS ACTIVITY BUT MOST OF THESE TSTMS SHOULD BE FARTHER E ACROSS THE TOLEDO BEND COUNTRY AND INTO CNTRL LA. /09/ && .PREV DISCUSSION... /ISSUED 1159 AM CDT SUN AUG 17 2014/ DISCUSSION... MADE A FEW CHANGES TO THE CURRENT FORECAST. BUMPED UP THE DAYTIME HIGHS FOR THE EAST TEXAS...SOUTHWEST ARKANSAS...AND NORTHWEST AND NORTH CENTRAL LOUISIANA ZONES GIVEN THAT MORE SUN HAS BEEN PEEKING THROUGH WITH LESS CLOUD COVER AND SPARSE COVERAGE OF ANY RAINFALL. THE AREA OF SHOWERS AND THUNDERSTORMS TO THE WEST HAS NOT MADE MUCH PROGRESS INTO THE FORECAST AREA EVEN WITH A DISTURBANCE/SHEAR AXIS OVERHEAD. A TIGHT PRESSURE GRADIENT OVER PARTS OF THE AREA HAS REQUIRED THE WINDS TO BE INCREASED SLIGHTLY. /06/ PREV DISCUSSION... /ISSUED 450 AM CDT SUN AUG 17 2014/ DISCUSSION... SCT CONVECTION HAS REDEVELOPED THIS MORNING N OF THE I-30 CORRIDOR OF NE TX/SW AR EARLY THIS MORNING...WHICH IS OCCURRING NEAR AND NORTH OF AN OLD OUTFLOW BNDRY FROM SATURDAY EVENING/S CONVECTION. THE CONVECTION APPEARS TO BE AIDED BY WEAK FORCING ASSOCIATED WITH A 25KT SWRLY LLJ ATOP THE COOL/STABLE AIR AND WEAK PVA AHEAD OF A SHEAR AXIS NOW EXTENDING FROM NCNTRL AR SW INTO SE OK/EXTREME NE TX AND INTO CNTRL TX. MOSAIC RADAR LOOP ACTUALLY REVEALS A MCV EMBEDDED WITHIN THE SHEAR AXIS ITSELF OVER JUST N OF DTO NEAR THE RED RIVER...WHERE ELEVATED THUNDER HAS RECENTLY DEVELOPED. THE SHORT TERM PROGS HAVE INITIALIZED POORLY THIS MORNING WITH THE ONGOING CONVECTION...WITH THE HRRR SEVERAL HOURS TOO SLOW WITH THE CURRENT ELEVATED -SHRA OVER EXTREME NE TX/SE OK/SW AR. WITH THIS IN MIND...CONFIDENCE IS LOW WITH THE TIMING/EXACT PLACEMENT OF CONVECTION TODAY...BUT HAVE TRENDED THE FORECAST CLOSER TO THE WRF SOLUTION WHICH SHOWS MUCH LESS FEEDBACK THAN THE GFS...AND HAS BEEN MORE CONSISTENT IN THE SLOWER MOVEMENT OF THE SHEAR AXIS AS IT DRIFTS SE INTO SW AR/EXTREME SE OK/NE TX THIS AFTERNOON. EXTENSIVE ELEVATED CONVECTIVE DEBRIS AND CONVECTIVE REDEVELOPMENT SHOULD HELP HOLD MAX TEMPS DOWN SEVERAL DEGREES COOLER THAN WHAT WAS OBSERVED SATURDAY OVER THE NW ZONES...WITH THE HOTTEST TEMPS FARTHER SSE OVER DEEP E TX/NCNTRL LA. SHOULD AGAIN SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES THIS AFTERNOON WHICH SHOULD DIMINISH DURING THE EARLY EVENING...WITH THE SHEAR AXIS SETTLING TO NEAR THE I-20 CORRIDOR OF E TX INTO EXTREME NW LA/SW AR. HAVE MAINTAINED MID CHANCE POPS TODAY/TONIGHT ALONG THE AXIS ITSELF...BEFORE IT DRIFTS FARTHER ESE TO NEAR THE I-20 CORRIDOR OF N LA MONDAY. THE PROGS HAVE CONTINUED THE TREND WITH A MORE SWD PLACEMENT OF THIS FEATURE FOR THE LAST FEW DAYS...BUT DON/T THINK IT SHOULD ADVANCE MUCH FARTHER S AS THE PARENT SHORTWAVE ENERGY ACROSS THE MID-SOUTH AND LOWER MS VALLEY BEGINS TO SHIFT E AWAY FROM THE AREA. ELEVATED CONVECTIVE DEBRIS AND WIDELY SCT CONVECTION SHOULD AGAIN HELP RETARD HEATING SLIGHTLY MONDAY...BEFORE THE SHEAR AXIS BEGINS TO WEAKEN BY TUESDAY AS UPPER RIDGING SHIFTS E INTO THE SRN PLAINS FROM THE SRN ROCKIES...AND THE WRN ATLANTIC/ERN GULF OF MX RIDGE BEGINS TO EXPAND W ACROSS THE REMAINDER OF THE GULF. THUS...CONVECTION SHOULD BECOME MORE ISOLATED AND CONFINED MAINLY TO PORTIONS OF E TX/N LA TUESDAY AFTERNOON. SHOULD START TO SEE HOTTER TEMPS RETURN BY THIS TIME...WITH THE HEAT BUILDING EVEN MORE WEDNESDAY THROUGH THE REMAINDER OF THE EXTENDED AFTER THE SHEAR AXIS FILLS...AND RIDGING ALOFT EXPANDS FARTHER W ACROSS THE GULF STATES. STILL APPEARS ISOLATED CONVECTION WILL BE POSSIBLE WEDNESDAY AND THURSDAY AFTERNOONS IN RESPONSE TO A WEAK SEABREEZE...BUT THE REMAINDER OF THE EXTENDED WILL REMAIN VERY HOT AND DRY GIVEN THE INCREASED SUBSIDENCE BENEATH THE RIDGE. IN FACT...CAN/T RULE OUT NEAR TRIPLE DIGIT HEAT RETURNING TO PORTIONS OF THE REGION NEXT WEEKEND/EARLY NEXT WEEK AS AVAILABLE SOIL MOISTURE CONTINUES TO DRY...AND SOIL TEMPS QUICKLY HEAT UP. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 93 76 96 / 20 40 30 20 20 MLU 95 74 93 75 95 / 20 30 30 20 20 DEQ 92 72 94 72 94 / 40 20 20 10 10 TXK 93 75 94 74 95 / 40 40 20 10 10 ELD 93 74 93 74 95 / 20 40 30 10 10 TYR 94 75 94 75 96 / 30 40 30 10 10 GGG 94 75 93 75 96 / 30 40 30 10 10 LFK 96 76 94 76 96 / 30 30 20 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1159 AM CDT SUN AUG 17 2014 .DISCUSSION... MADE A FEW CHANGES TO THE CURRENT FORECAST. BUMPED UP THE DAYTIME HIGHS FOR THE EAST TEXAS...SOUTHWEST ARKANSAS...AND NORTHWEST AND NORTH CENTRAL LOUISIANA ZONES GIVEN THAT MORE SUN HAS BEEN PEEKING THROUGH WITH LESS CLOUD COVER AND SPARSE COVERAGE OF ANY RAINFALL. THE AREA OF SHOWERS AND THUNDERSTORMS TO THE WEST HAS NOT MADE MUCH PROGRESS INTO THE FORECAST AREA EVEN WITH A DISTURBANCE/SHEAR AXIS OVERHEAD. A TIGHT PRESSURE GRADIENT OVER PARTS OF THE AREA HAS REQUIRED THE WINDS TO BE INCREASED SLIGHTLY. /06/ && .PREV DISCUSSION... /ISSUED 535 AM CDT SUN AUG 17 2014/ AVIATION... MOSTLY VFR CONDITIONS ACROSS AREA THIS MORNING....EXCEPT FOR NE TX..WHERE LOW MVFR CIGS SPREADING EASTARD. FURTHER NORTH...SCATTERED LGT RW...MOSTLY FROM MID LVL CLOUD BASES...WILL LIKELY INTENSIFY WITH DAYTIME HEATING. A FEW TSTMS POSSIBLE THIS AFTN...MAINLY AT KTXK...KTYR...AND KGGG TERMINALS. REMAINING TERMINALS LIKELY NOT SEE TSTMS UNTIL AFTER 08/00Z. SW WINDS TO INCREASE TO AROUND 10 KTS BY MIDDAY...STGR GUSTS POSSIBLE NEAR STORMS GIVEN STEEP LOW LVL LAPSE RATES./VII/. PREV DISCUSSION... /ISSUED 450 AM CDT SUN AUG 17 2014/ DISCUSSION... SCT CONVECTION HAS REDEVELOPED THIS MORNING N OF THE I-30 CORRIDOR OF NE TX/SW AR EARLY THIS MORNING...WHICH IS OCCURRING NEAR AND NORTH OF AN OLD OUTFLOW BNDRY FROM SATURDAY EVENING/S CONVECTION. THE CONVECTION APPEARS TO BE AIDED BY WEAK FORCING ASSOCIATED WITH A 25KT SWRLY LLJ ATOP THE COOL/STABLE AIR AND WEAK PVA AHEAD OF A SHEAR AXIS NOW EXTENDING FROM NCNTRL AR SW INTO SE OK/EXTREME NE TX AND INTO CNTRL TX. MOSAIC RADAR LOOP ACTUALLY REVEALS A MCV EMBEDDED WITHIN THE SHEAR AXIS ITSELF OVER JUST N OF DTO NEAR THE RED RIVER...WHERE ELEVATED THUNDER HAS RECENTLY DEVELOPED. THE SHORT TERM PROGS HAVE INITIALIZED POORLY THIS MORNING WITH THE ONGOING CONVECTION...WITH THE HRRR SEVERAL HOURS TOO SLOW WITH THE CURRENT ELEVATED -SHRA OVER EXTREME NE TX/SE OK/SW AR. WITH THIS IN MIND...CONFIDENCE IS LOW WITH THE TIMING/EXACT PLACEMENT OF CONVECTION TODAY...BUT HAVE TRENDED THE FORECAST CLOSER TO THE WRF SOLUTION WHICH SHOWS MUCH LESS FEEDBACK THAN THE GFS...AND HAS BEEN MORE CONSISTENT IN THE SLOWER MOVEMENT OF THE SHEAR AXIS AS IT DRIFTS SE INTO SW AR/EXTREME SE OK/NE TX THIS AFTERNOON. EXTENSIVE ELEVATED CONVECTIVE DEBRIS AND CONVECTIVE REDEVELOPMENT SHOULD HELP HOLD MAX TEMPS DOWN SEVERAL DEGREES COOLER THAN WHAT WAS OBSERVED SATURDAY OVER THE NW ZONES...WITH THE HOTTEST TEMPS FARTHER SSE OVER DEEP E TX/NCNTRL LA. SHOULD AGAIN SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES THIS AFTERNOON WHICH SHOULD DIMINISH DURING THE EARLY EVENING...WITH THE SHEAR AXIS SETTLING TO NEAR THE I-20 CORRIDOR OF E TX INTO EXTREME NW LA/SW AR. HAVE MAINTAINED MID CHANCE POPS TODAY/TONIGHT ALONG THE AXIS ITSELF...BEFORE IT DRIFTS FARTHER ESE TO NEAR THE I-20 CORRIDOR OF N LA MONDAY. THE PROGS HAVE CONTINUED THE TREND WITH A MORE SWD PLACEMENT OF THIS FEATURE FOR THE LAST FEW DAYS...BUT DON/T THINK IT SHOULD ADVANCE MUCH FARTHER S AS THE PARENT SHORTWAVE ENERGY ACROSS THE MID-SOUTH AND LOWER MS VALLEY BEGINS TO SHIFT E AWAY FROM THE AREA. ELEVATED CONVECTIVE DEBRIS AND WIDELY SCT CONVECTION SHOULD AGAIN HELP RETARD HEATING SLIGHTLY MONDAY...BEFORE THE SHEAR AXIS BEGINS TO WEAKEN BY TUESDAY AS UPPER RIDGING SHIFTS E INTO THE SRN PLAINS FROM THE SRN ROCKIES...AND THE WRN ATLANTIC/ERN GULF OF MX RIDGE BEGINS TO EXPAND W ACROSS THE REMAINDER OF THE GULF. THUS...CONVECTION SHOULD BECOME MORE ISOLATED AND CONFINED MAINLY TO PORTIONS OF E TX/N LA TUESDAY AFTERNOON. SHOULD START TO SEE HOTTER TEMPS RETURN BY THIS TIME...WITH THE HEAT BUILDING EVEN MORE WEDNESDAY THROUGH THE REMAINDER OF THE EXTENDED AFTER THE SHEAR AXIS FILLS...AND RIDGING ALOFT EXPANDS FARTHER W ACROSS THE GULF STATES. STILL APPEARS ISOLATED CONVECTION WILL BE POSSIBLE WEDNESDAY AND THURSDAY AFTERNOONS IN RESPONSE TO A WEAK SEABREEZE...BUT THE REMAINDER OF THE EXTENDED WILL REMAIN VERY HOT AND DRY GIVEN THE INCREASED SUBSIDENCE BENEATH THE RIDGE. IN FACT...CAN/T RULE OUT NEAR TRIPLE DIGIT HEAT RETURNING TO PORTIONS OF THE REGION NEXT WEEKEND/EARLY NEXT WEEK AS AVAILABLE SOIL MOISTURE CONTINUES TO DRY...AND SOIL TEMPS QUICKLY HEAT UP. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 93 76 96 / 20 40 30 20 20 MLU 95 74 93 75 95 / 20 30 30 20 20 DEQ 92 72 94 72 94 / 40 20 20 10 10 TXK 93 75 94 74 95 / 40 40 20 10 10 ELD 93 74 93 74 95 / 20 40 30 10 10 TYR 94 75 94 75 96 / 30 40 30 10 10 GGG 94 75 93 75 96 / 30 40 30 10 10 LFK 96 76 94 76 96 / 30 30 20 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 06
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
535 AM CDT SUN AUG 17 2014 .AVIATION... MOSTLY VFR CONDITIONS ACROSS AREA THIS MORNING....EXCEPT FOR NE TX..WHERE LOW MVFR CIGS SPREADING EASTARD. FURTHER NORTH...SCATTERED LGT RW...MOSTLY FROM MID LVL CLOUD BASES...WILL LIKELY INTENSIFY WITH DAYTIME HEATING. A FEW TSTMS POSSIBLE THIS AFTN...MAINLY AT KTXK...KTYR...AND KGGG TERMINALS. REMAINING TERMINALS LIKELY NOT SEE TSTMS UNTIL AFTER 08/00Z. SW WINDS TO INCREASE TO AROUND 10 KTS BY MIDDAY...STGR GUSTS POSSIBLE NEAR STORMS GIVEN STEEP LOW LVL LAPSE RATES./VII/. && .PREV DISCUSSION... /ISSUED 450 AM CDT SUN AUG 17 2014/ DISCUSSION... SCT CONVECTION HAS REDEVELOPED THIS MORNING N OF THE I-30 CORRIDOR OF NE TX/SW AR EARLY THIS MORNING...WHICH IS OCCURRING NEAR AND NORTH OF AN OLD OUTFLOW BNDRY FROM SATURDAY EVENING/S CONVECTION. THE CONVECTION APPEARS TO BE AIDED BY WEAK FORCING ASSOCIATED WITH A 25KT SWRLY LLJ ATOP THE COOL/STABLE AIR AND WEAK PVA AHEAD OF A SHEAR AXIS NOW EXTENDING FROM NCNTRL AR SW INTO SE OK/EXTREME NE TX AND INTO CNTRL TX. MOSAIC RADAR LOOP ACTUALLY REVEALS A MCV EMBEDDED WITHIN THE SHEAR AXIS ITSELF OVER JUST N OF DTO NEAR THE RED RIVER...WHERE ELEVATED THUNDER HAS RECENTLY DEVELOPED. THE SHORT TERM PROGS HAVE INITIALIZED POORLY THIS MORNING WITH THE ONGOING CONVECTION...WITH THE HRRR SEVERAL HOURS TOO SLOW WITH THE CURRENT ELEVATED -SHRA OVER EXTREME NE TX/SE OK/SW AR. WITH THIS IN MIND...CONFIDENCE IS LOW WITH THE TIMING/EXACT PLACEMENT OF CONVECTION TODAY...BUT HAVE TRENDED THE FORECAST CLOSER TO THE WRF SOLUTION WHICH SHOWS MUCH LESS FEEDBACK THAN THE GFS...AND HAS BEEN MORE CONSISTENT IN THE SLOWER MOVEMENT OF THE SHEAR AXIS AS IT DRIFTS SE INTO SW AR/EXTREME SE OK/NE TX THIS AFTERNOON. EXTENSIVE ELEVATED CONVECTIVE DEBRIS AND CONVECTIVE REDEVELOPMENT SHOULD HELP HOLD MAX TEMPS DOWN SEVERAL DEGREES COOLER THAN WHAT WAS OBSERVED SATURDAY OVER THE NW ZONES...WITH THE HOTTEST TEMPS FARTHER SSE OVER DEEP E TX/NCNTRL LA. SHOULD AGAIN SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES THIS AFTERNOON WHICH SHOULD DIMINISH DURING THE EARLY EVENING...WITH THE SHEAR AXIS SETTLING TO NEAR THE I-20 CORRIDOR OF E TX INTO EXTREME NW LA/SW AR. HAVE MAINTAINED MID CHANCE POPS TODAY/TONIGHT ALONG THE AXIS ITSELF...BEFORE IT DRIFTS FARTHER ESE TO NEAR THE I-20 CORRIDOR OF N LA MONDAY. THE PROGS HAVE CONTINUED THE TREND WITH A MORE SWD PLACEMENT OF THIS FEATURE FOR THE LAST FEW DAYS...BUT DON/T THINK IT SHOULD ADVANCE MUCH FARTHER S AS THE PARENT SHORTWAVE ENERGY ACROSS THE MID-SOUTH AND LOWER MS VALLEY BEGINS TO SHIFT E AWAY FROM THE AREA. ELEVATED CONVECTIVE DEBRIS AND WIDELY SCT CONVECTION SHOULD AGAIN HELP RETARD HEATING SLIGHTLY MONDAY...BEFORE THE SHEAR AXIS BEGINS TO WEAKEN BY TUESDAY AS UPPER RIDGING SHIFTS E INTO THE SRN PLAINS FROM THE SRN ROCKIES...AND THE WRN ATLANTIC/ERN GULF OF MX RIDGE BEGINS TO EXPAND W ACROSS THE REMAINDER OF THE GULF. THUS...CONVECTION SHOULD BECOME MORE ISOLATED AND CONFINED MAINLY TO PORTIONS OF E TX/N LA TUESDAY AFTERNOON. SHOULD START TO SEE HOTTER TEMPS RETURN BY THIS TIME...WITH THE HEAT BUILDING EVEN MORE WEDNESDAY THROUGH THE REMAINDER OF THE EXTENDED AFTER THE SHEAR AXIS FILLS...AND RIDGING ALOFT EXPANDS FARTHER W ACROSS THE GULF STATES. STILL APPEARS ISOLATED CONVECTION WILL BE POSSIBLE WEDNESDAY AND THURSDAY AFTERNOONS IN RESPONSE TO A WEAK SEABREEZE...BUT THE REMAINDER OF THE EXTENDED WILL REMAIN VERY HOT AND DRY GIVEN THE INCREASED SUBSIDENCE BENEATH THE RIDGE. IN FACT...CAN/T RULE OUT NEAR TRIPLE DIGIT HEAT RETURNING TO PORTIONS OF THE REGION NEXT WEEKEND/EARLY NEXT WEEK AS AVAILABLE SOIL MOISTURE CONTINUES TO DRY...AND SOIL TEMPS QUICKLY HEAT UP. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 94 75 93 76 96 / 20 40 30 20 20 MLU 94 74 93 75 95 / 20 30 30 20 20 DEQ 91 72 94 72 94 / 40 20 20 10 10 TXK 91 75 94 74 95 / 40 40 20 10 10 ELD 93 74 93 74 95 / 20 40 30 10 10 TYR 92 75 94 75 96 / 40 40 30 10 10 GGG 93 75 93 75 96 / 30 40 30 10 10 LFK 95 76 94 76 96 / 30 30 20 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
450 AM CDT SUN AUG 17 2014 .DISCUSSION... SCT CONVECTION HAS REDEVELOPED THIS MORNING N OF THE I-30 CORRIDOR OF NE TX/SW AR EARLY THIS MORNING...WHICH IS OCCURRING NEAR AND NORTH OF AN OLD OUTFLOW BNDRY FROM SATURDAY EVENING/S CONVECTION. THE CONVECTION APPEARS TO BE AIDED BY WEAK FORCING ASSOCIATED WITH A 25KT SWRLY LLJ ATOP THE COOL/STABLE AIR AND WEAK PVA AHEAD OF A SHEAR AXIS NOW EXTENDING FROM NCNTRL AR SW INTO SE OK/EXTREME NE TX AND INTO CNTRL TX. MOSAIC RADAR LOOP ACTUALLY REVEALS A MCV EMBEDDED WITHIN THE SHEAR AXIS ITSELF OVER JUST N OF DTO NEAR THE RED RIVER...WHERE ELEVATED THUNDER HAS RECENTLY DEVELOPED. THE SHORT TERM PROGS HAVE INITIALIZED POORLY THIS MORNING WITH THE ONGOING CONVECTION...WITH THE HRRR SEVERAL HOURS TOO SLOW WITH THE CURRENT ELEVATED -SHRA OVER EXTREME NE TX/SE OK/SW AR. WITH THIS IN MIND...CONFIDENCE IS LOW WITH THE TIMING/EXACT PLACEMENT OF CONVECTION TODAY...BUT HAVE TRENDED THE FORECAST CLOSER TO THE WRF SOLUTION WHICH SHOWS MUCH LESS FEEDBACK THAN THE GFS...AND HAS BEEN MORE CONSISTENT IN THE SLOWER MOVEMENT OF THE SHEAR AXIS AS IT DRIFTS SE INTO SW AR/EXTREME SE OK/NE TX THIS AFTERNOON. EXTENSIVE ELEVATED CONVECTIVE DEBRIS AND CONVECTIVE REDEVELOPMENT SHOULD HELP HOLD MAX TEMPS DOWN SEVERAL DEGREES COOLER THAN WHAT WAS OBSERVED SATURDAY OVER THE NW ZONES...WITH THE HOTTEST TEMPS FARTHER SSE OVER DEEP E TX/NCNTRL LA. SHOULD AGAIN SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES THIS AFTERNOON WHICH SHOULD DIMINISH DURING THE EARLY EVENING...WITH THE SHEAR AXIS SETTLING TO NEAR THE I-20 CORRIDOR OF E TX INTO EXTREME NW LA/SW AR. HAVE MAINTAINED MID CHANCE POPS TODAY/TONIGHT ALONG THE AXIS ITSELF...BEFORE IT DRIFTS FARTHER ESE TO NEAR THE I-20 CORRIDOR OF N LA MONDAY. THE PROGS HAVE CONTINUED THE TREND WITH A MORE SWD PLACEMENT OF THIS FEATURE FOR THE LAST FEW DAYS...BUT DON/T THINK IT SHOULD ADVANCE MUCH FARTHER S AS THE PARENT SHORTWAVE ENERGY ACROSS THE MID-SOUTH AND LOWER MS VALLEY BEGINS TO SHIFT E AWAY FROM THE AREA. ELEVATED CONVECTIVE DEBRIS AND WIDELY SCT CONVECTION SHOULD AGAIN HELP RETARD HEATING SLIGHTLY MONDAY...BEFORE THE SHEAR AXIS BEGINS TO WEAKEN BY TUESDAY AS UPPER RIDGING SHIFTS E INTO THE SRN PLAINS FROM THE SRN ROCKIES...AND THE WRN ATLANTIC/ERN GULF OF MX RIDGE BEGINS TO EXPAND W ACROSS THE REMAINDER OF THE GULF. THUS...CONVECTION SHOULD BECOME MORE ISOLATED AND CONFINED MAINLY TO PORTIONS OF E TX/N LA TUESDAY AFTERNOON. SHOULD START TO SEE HOTTER TEMPS RETURN BY THIS TIME...WITH THE HEAT BUILDING EVEN MORE WEDNESDAY THROUGH THE REMAINDER OF THE EXTENDED AFTER THE SHEAR AXIS FILLS...AND RIDGING ALOFT EXPANDS FARTHER W ACROSS THE GULF STATES. STILL APPEARS ISOLATED CONVECTION WILL BE POSSIBLE WEDNESDAY AND THURSDAY AFTERNOONS IN RESPONSE TO A WEAK SEABREEZE...BUT THE REMAINDER OF THE EXTENDED WILL REMAIN VERY HOT AND DRY GIVEN THE INCREASED SUBSIDENCE BENEATH THE RIDGE. IN FACT...CAN/T RULE OUT NEAR TRIPLE DIGIT HEAT RETURNING TO PORTIONS OF THE REGION NEXT WEEKEND/EARLY NEXT WEEK AS AVAILABLE SOIL MOISTURE CONTINUES TO DRY...AND SOIL TEMPS QUICKLY HEAT UP. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 94 75 93 76 96 / 20 40 30 20 20 MLU 94 74 93 75 95 / 20 30 30 20 20 DEQ 91 72 94 72 94 / 40 20 20 10 10 TXK 91 75 94 74 95 / 40 40 20 10 10 ELD 93 74 93 74 95 / 20 40 30 10 10 TYR 92 75 94 75 96 / 40 40 30 10 10 GGG 93 75 93 75 96 / 30 40 30 10 10 LFK 95 76 94 76 96 / 30 30 20 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 15
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1158 PM CDT SAT AUG 16 2014 .AVIATION... TSTMS HAVE DIMINISHED ACROSS THE ARKLATEX FOR THE TIME BEING. HOWEVER...MORE HAVE DEVELOPED OVER N TX...AND IT IS POSSIBLE THAT SOME OF THESE COULD WORK THEIR WAY INTO THE REGION DURING THE OVERNIGHT HOURS. ADDITIONALY...MVFR/PATCHY IFR CIGS/VSBYS WILL BE POSSIBLE AROUND SUNRISE...AS LL MOISTURE CONTINUES TO INCREASE. VFR CONDITIONS ARE EXPECTED TO RETURN BY MID MORNING...WITH CONVECTION POSSIBLE AGAIN SUNDAY PRIMARILY DURING PEAK HEATING. COVERAGE IS EXPECTED TO BE TOO ISOLD/UNCERTAIN TO WARRANT MENTION IN THE TAFS OUTSIDE OF VCTS ATTM. /12/ && .PREV DISCUSSION... /ISSUED 944 PM CDT SAT AUG 16 2014/ DISCUSSION... CONVECTION DEVELOPED RIGHT AS PLANNED ALONG AND NORTHWEST OF THE I-30 CORRIDOR OF NE TX THIS EVENING. WEAK COLD POOL FORMED AND HAS SINCE MOVED WELL SOUTHEAST OF WHAT CONVECTION WE HAVE LEFT OVER ACROSS NE TX/SE OK AND SW AR. LOTS OF THINGS TO CONSIDER FOR AN UPDATE THIS EVENING THROUGH TOMORROW. ONE OF WHICH WILL BE A PERSISTENT ELEVATED THETA-E BOUNDARY ACROSS OUR NW ZONES...RELATIVELY HIGH PWAT VALUES REMAINING IN PLACE...NOT TO MENTION A WEAK SHEAR AXIS THAT WILL REMAIN ANCHORED ACROSS THE REGION AS WELL. AFTER HAVING COORDINATED WITH THE FWD OFFICE...WE WILL CONTINUE TO HOLD ON TO CHANCE POPS ALONG AND NORTHWEST OF A LINE FROM TYR AND GGG TO NEAR TXK FOR THE REMAINDER OF THE NIGHT. HRRR OUTPUT DOES NOT SUPPORT REDEVELOPMENT ACROSS OUR NW ZONES AND THE NEW 00Z NAM OUTPUT DOES NOT SUPPORT MUCH EITHER AND WHILE THE 18Z GFS OUTPUT IS OBVIOUSLY SHOWING CONVECTIVE FEEDBACK PROBLEMS...CANNOT RULE OUT THE POSSIBILITY OF REDEVELOPMENT EVEN THOUGH I WOULD LIKE TO SEE MORE THAN 15KTS WORTH OF A LOW LEVEL SOUTHWEST JET OVERNIGHT. FOR THE TEMPERATURE FORECAST...24HR TEMPERATURE CHANGES COMPARED TO THIS TIME LAST NIGHT ARE SHOWING AN AVERAGE OF 4 TO 7 DEGREES WARMER THAN THIS TIME LAST NIGHT WITH A SLIGHTLY LOWER AVERAGE FOR DEWPOINTS AS WELL. FOR THIS REASON...HAVE RAISED OVERNIGHT MIN TEMPERATURES ACROSS THE BOARD AS WELL. OTHER THAN ADDITIONAL CHANGES TO DEWPOINT/RH GRIDS...ALL OTHER GRIDS ARE IN GOOD SHAPE AND NO OTHER CHANGES WERE NECESSARY ATTM. /13/ && .PRELIMINARY POINT TEMPS/POPS... SHV 76 93 73 94 74 / 10 30 20 20 10 MLU 74 92 73 94 73 / 10 30 20 30 20 DEQ 73 91 71 93 73 / 30 40 20 20 20 TXK 76 92 73 94 74 / 30 40 20 20 10 ELD 74 92 73 93 73 / 10 30 20 30 20 TYR 78 94 75 95 76 / 30 40 20 20 10 GGG 76 93 75 95 75 / 30 40 20 20 10 LFK 78 94 75 94 74 / 10 30 20 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 12
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
935 PM EDT MON AUG 18 2014 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP OVER VIRGINIA TONIGHT BEFORE MOVING OFF THE COAST TUESDAY. WEAK HIGH PRESSURE RETURNS ON WEDNESDAY BEFORE ANOTHER SYSTEM OVER THE GREAT LAKES MOVES INTO THE MID ATLANTIC STATES FOR THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... BANDS OF SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA OVER THE NEXT SEVERAL HOURS AND OVERNIGHT. THE HRRR AND RAP RE BOTH DOING A GOOD JOB HANDLING THE SURFACE LOW OVER CENTRAL NE LIFTING IT NORTH INTO VA AND MERGING IT WITH THE BROAD LOW JUST TO THE WEST. PRECIP COVERAGE WILL BE GREATEST ACROSS SOUTH CENTRAL VA...TIDEWATER...HAMPTON ROADS AND NORTHEAST NC. ALSO EXPECT THE LINGERING SHOWER TO PERSIST NORTH OF RIC FROM LOUISA AND ESPECIALLY INTO CAROLINE. OVERNIGHT ACTIVITY SHOULD REMAIN MOSTLY SHOWERS WITH LITTLE TO NO THUNDER. A FEW LOCATIONS COULD SEE 0.50 OR MORE OF RAIN OVERNIGHT AS PWATS CONTINUE TO RUN A LITTLE OVER 2 INCHES IN A VERY MOIST ATMOSPHERE. OVERNIGHT LOWS WILL HOVER IN THE LOW TO MID 70S DUE TO THE MORE HUMID AIRMASS. FOR TUESDAY...THE LOW SLOWLY SLIDES OFF THE VA COAST AND HAS SOME WRAP AROUND MOISTURE SO HAVE HELD ON TO THE PCPN A LITTLE LONGER ACROSS THE DELMARVA AS THE 12Z NAM IS SLOWER THAN THE 12Z GFS IN PULLING THE LOW OUT. LATER IN THE AFTERNOON...WILL GET THE SFC BOUNDARY SLIDING DOWN INTO THE TIDEWATER AND NE NC SO MORE SHOWERS ARE POSSIBLE THERE. FOR TEMPERATURES HAVE LEAN A LITTLE LOW ESPECIALLY TOWARD THE NORTH THINKING THAT CLOUDS WILL LINGER AND LIMIT THE DAY TIME HEATING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... FROM TUESDAY NIGHT THROUGH THURSDAY...THE MODELS ARE SHOWING LOTS OF VARIABLIITY WITH THE MOVEMENT OF SHORTWAVE ENERGY IN THE NORTHWEST FLOW AS THE UPPER RIDGE OVER THE MS VALLEY BUILDS AND THE UPPER LOW OVER THE GREAT LAKES IS SLOW TO MOVE EAST. WEDNESDAY LOOKS TO BE THE DRIER OF THE TWO DAY AS THE EXITING LOW OFF THE COAST ALLOWS FOR WEAK HIGH PRESSURE OVER THE NE TO NOSE SOUTHWARD INTO THE MID ATLANTIC STATES AND THE MOISTURE LESSENS. BUT BY THURSDAY...THE NW FLOW IS MORE ESTABLISHED AND WITH CONVECTION TO THE NORTHWEST AND THE REGION IN A GOOD POSITION ON THE EDGE OF THE RIDGE...COULD EASILY SEE CONVECTION DROP SE INTO THE REGION. SO HAVE VERY LITTLE PCPN ON WEDNESDAY WITH HIGHER CHANCE POPS ON THURSDAY. BUT CONFIDENCE IN THE OVER PATTERN IS LOW DUE TO THE MODEL UNCERTAINTY FROM RUN TO RUN. FOR TEMPERATURES...HAVE ALLOWED FOR SOME ADDITIONAL HEATING ON WED AND THU DUE TO MORE SUNSHINE AND ALSO DUE TO THE WEST/NW FLOW ALOFT. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... UNSETTLED WEATHER PATTERN CONTINUES INTO THE EXTENDED PERIOD AS NWLY FLOW ALOFT DEVELOPS. TEMPS WILL BE NEAR TO SLIGHTLY BELOW SEASONABLE...LATE SUMMER NORMS. WHILE MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE HANDLING THE SPLIT/BLOCKY FLOW OVER THE HIGHER LATITUDES...MODELS HAVE BECOME MORE STABLE WITH RESOLVING SRN STREAM ENERGY OVER THE OH VALLEY AND MID-ATLANTIC REGION. THIS THANKS TO UPPER/SFC HIGH PRESSURE FROM THE SE STATES EWD OFF THE COAST. WITH THAT SAID...FLOW AMPLIFIES OVER THE ERN CONUS AS MID LEVEL HIGH PRESSURE BUILDS OVER THE CNTRL US AND LOW PRESSURE REMAINS OVER THE NE US. THIS WILL PLACE THE MID-ATLANTIC STATES IN NWLY FLOW ALOFT...OPENING THE DOOR FOR SHORTWAVE ENERGY IN THE UPPER FLOW. QUASI-STATIONARY BOUNDARY WILL LOCATE OVER THE REGION...JUST TO THE SOUTH. MOISTURE WILL NOT BE A LIMITATION WITH PWATS PROGGED AROUND 2 INCHES (+1 STD DEV) AND DEWPOINTS IN THE MID-UPPER 60S. ANTICIPATE A DIURNAL TREND WITH SHOWERS/THUNDERSTORMS...BUT UPSTREAM MCS DEVELOPMENT MAY SPILL INTO THE REGION DURING THE OVERNIGHT HOURS THRU THE WEEKEND. HIGHER POPS MAY BE WARRANTED...BUT BASED ON THE DEGREE OF UNCERTAINTY AND TIMING...WILL STICK MORE TO CLIMO WITH CHANCE POPS DURING THE AFTERNOON AND EVENING. COULD BEGIN TO SEE A DRYING TREND BY LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS THE UPPER HIGH BUILDS EWD...SHUNTING THE BEST MOISTURE OFFSHORE. WITH THE LATEST MODEL RUNS PLACING THE FRONT SOUTH OF THE LOCAL AREA...NLY FLOW AND FALLING THICKNESSES WILL LIKELY YIELD TEMPS IN THE LOW-MID 80S. LOW-MID 80S TO CONTINUE THRU THE WEEKEND...WARMING BACK INTO THE MID 80S BY EARLY NEXT WEEK. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... A COMPLEX AREA OF LOW PRESSURE AND FRONTAL SYSTEMS COVERED THE MID ATLANTIC STATES MONDAY EVENING. LOW PRESSURE MOVES OFF THE COAST TUESDAY MORNING WITH WEAK HIGH PRESSURE BUILDING FROM THE NORTH THROUGH WEDNESDAY. UNSETTLED WEATHER RETURNS LATE IN THE WEEK. THE LINE OF TSTMS THAT AFFECTED SOUTHEAST VIRGINIA MOVED OFF THE COAST JUST PRIOR TO THE 00Z TAF ISSUANCE MORE SHOWERS WERE DEVELOPING BUT NO SIGNIFICANT TSTMS ARE EXPECTED OVERNIGHT. WITH MOIST CONDITIONS... MVFR WITH AREAS OF IFR CAN BE EXPECTED IN THE LATE EVENING AND OVERNIGHT. MVFR SHOULD END BY LATE MORNING. WIDELY SCT SHOWERS AND TSTMS WILL BE PSBL TUESDAY BUT NOT NEARLY AS WIDESPREAD AS THEY WERE MONDAY. OUTLOOK...SCT AFTN/EVENING TSTMS RETURN TO THE FCST THURSDAY THROUGH SATURDAY. THERE WILL BE THE POSSIBILITY OF MVFR/IFR CONDS WITHIN A FEW HOURS OF SUNRISE EACH MORNING. && .MARINE... UNSETTLED WEATHER PATTERN WILL PREVAIL OVER THE WATERS THRU THE FORECAST PERIOD...BUT SCA CONDITIONS ARE NOT ANTICIPATED. AREA OF LOW PRESSURE HAS LOCATED OVER WV WITH A FRONTAL BOUNDARY EXTENDING EWD OVER SRN VA AND THE LOWER BAY. MEANWHILE...HIGH PRESSURE BUILDS OVER THE NE STATES. THE RESULT IS GENERALLY ONSHORE AROUND 10 KT. WAVES/SEAS AVG 1-2 FT. SFC LOW WEAKENS OVER THE CNTRL APPALACHIANS AS AN ADDITIONAL AREA OF LOW PRESSURE DEVELOPS OVER THE WATERS. WITH THE SFC LOW OVER THE WATERS...FLOW OVER THE COASTAL WATERS (ON THE ERN PERIPHERY OF THE LOW) WILL BE SW OVER THE SRN WATERS...VEERING TO E OVER THE NRN WATERS...AVG 10-15 KT. SCA CONDITIONS ARE NOT ANTICIPATED. SEAS WILL BUILD ONLY TO 2-3 FT WITH WAVES AVG 1-2 FT. SFC LOW SLOWLY PUSHES OFFSHORE LATE TUES-TUES NIGHT AS HIGH PRESSURE OFF THE NE COAST RIDGES SWD OVER THE NRN WATERS. FLOW REMAINS GENERALLY ONSHORE...AOB 15 KT. LOW PRESSURE LINGERS OFF THE MID-ATLANTIC COAST THRU THE END OF THE WORK WEEK AND INTO THE WEEKEND AS A FRONTAL BOUNDARY REMAINS SOUTH OF THE WATERS. THE RESULT WILL BE ONGOING ONSHORE/NELY FLOW. GRADIENT WILL REMAIN WEAK (AOB 15 KT)...BUT PERSISTENT NE FETCH MAY PUSH SEAS UPWARDS OF 5 FT IN THE NRN COASTAL WATERS FRIDAY NIGHT THRU THE WEEKEND. UNDERCUT WAVEWATCH AS GFS IS NOT THE PREFERRED MEDIUM RANGE MODEL. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...ESS NEAR TERM...ESS/JAO SHORT TERM...ESS LONG TERM...SAM AVIATION...LSA MARINE...SAM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
850 PM EDT MON AUG 18 2014 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP OVER VIRGINIA TONIGHT BEFORE MOVING OFF THE COAST TUESDAY. WEAK HIGH PRESSURE RETURNS ON WEDNESDAY BEFORE ANOTHER SYSTEM OVER THE GREAT LAKES MOVES INTO THE MID ATLANTIC STATES FOR THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... UPDATE THIS EVENING TO DROP THE WATCH AND TWEAK THE POPS SOME OVERNIGHT. AS SECONDARY LOW DEVELOPING OVER CENTRAL NC SHOULD BECOME THE DOMINANT LOW OVERNIGHT LIFTING NORTHEAST INTO NORTHEAST NC AND SOUTHEAST VA AND LOWER BAY. TRENDING TOWARDS THE HRRR POP TRENDS WITH THE MOST WIDESPREAD SHOWERS AND STORMS ACROSS THE SOUTHERN TWO THIRDS OF THE FORECAST AREA. EXPECT SCATTERED SHOWERS AND STORMS WELL NORTH AND NORTHWEST OF RIC. ONCE THE LOW BEGINS TO DEVELOP THIS EVENING...EXPECT TO SEE MORE SHOWERS AND AREAS OF RAIN FORM ALONG AN NORTH OF THE FRONT WITH MORE CONVECTIVE PRECIPITATION TO THE SOUTH OF IT. SOME AREAS COULD SEE 0.50 - 1 INCH OF RAIN AS PW CONTINUE TO RUN A LITTLE OVER 2 INCHES IN A VERY MOIST ATMOSPHERE. HAVE ALSO BUMPED UP OVERNIGHT LOWS DUE TO THE MORE HUMID AIRMASS. FOR TUESDAY...THE LOW SLOWLY SLIDES OFF THE VA COAST AND HAS SOME WRAP AROUND MOISTURE SO HAVE HELD ON TO THE PCPN A LITTLE LONGER ACROSS THE DELMARVA AS THE 12Z NAM IS SLOWER THAN THE 12Z GFS IN PULLING THE LOW OUT. LATER IN THE AFTERNOON...WILL GET THE SFC BOUNDARY SLIDING DOWN INTO THE TIDEWATER AND NE NC SO MORE SHOWERS ARE POSSIBLE THERE. FOR TEMPERATURES HAVE LEAN A LITTLE LOW ESPECIALLY TOWARD THE NORTH THINKING THAT CLOUDS WILL LINGER AND LIMIT THE DAY TIME HEATING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... FROM TUESDAY NIGHT THROUGH THURSDAY...THE MODELS ARE SHOWING LOTS OF VARIABLIITY WITH THE MOVEMENT OF SHORTWAVE ENERGY IN THE NORTHWEST FLOW AS THE UPPER RIDGE OVER THE MS VALLEY BUILDS AND THE UPPER LOW OVER THE GREAT LAKES IS SLOW TO MOVE EAST. WEDNESDAY LOOKS TO BE THE DRIER OF THE TWO DAY AS THE EXITING LOW OFF THE COAST ALLOWS FOR WEAK HIGH PRESSURE OVER THE NE TO NOSE SOUTHWARD INTO THE MID ATLANTIC STATES AND THE MOISTURE LESSENS. BUT BY THURSDAY...THE NW FLOW IS MORE ESTABLISHED AND WITH CONVECTION TO THE NORTHWEST AND THE REGION IN A GOOD POSITION ON THE EDGE OF THE RIDGE...COULD EASILY SEE CONVECTION DROP SE INTO THE REGION. SO HAVE VERY LITTLE PCPN ON WEDNESDAY WITH HIGHER CHANCE POPS ON THURSDAY. BUT CONFIDENCE IN THE OVER PATTERN IS LOW DUE TO THE MODEL UNCERTAINTY FROM RUN TO RUN. FOR TEMPERATURES...HAVE ALLOWED FOR SOME ADDITIONAL HEATING ON WED AND THU DUE TO MORE SUNSHINE AND ALSO DUE TO THE WEST/NW FLOW ALOFT. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... UNSETTLED WEATHER PATTERN CONTINUES INTO THE EXTENDED PERIOD AS NWLY FLOW ALOFT DEVELOPS. TEMPS WILL BE NEAR TO SLIGHTLY BELOW SEASONABLE...LATE SUMMER NORMS. WHILE MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE HANDLING THE SPLIT/BLOCKY FLOW OVER THE HIGHER LATITUDES...MODELS HAVE BECOME MORE STABLE WITH RESOLVING SRN STREAM ENERGY OVER THE OH VALLEY AND MID-ATLANTIC REGION. THIS THANKS TO UPPER/SFC HIGH PRESSURE FROM THE SE STATES EWD OFF THE COAST. WITH THAT SAID...FLOW AMPLIFIES OVER THE ERN CONUS AS MID LEVEL HIGH PRESSURE BUILDS OVER THE CNTRL US AND LOW PRESSURE REMAINS OVER THE NE US. THIS WILL PLACE THE MID-ATLANTIC STATES IN NWLY FLOW ALOFT...OPENING THE DOOR FOR SHORTWAVE ENERGY IN THE UPPER FLOW. QUASI-STATIONARY BOUNDARY WILL LOCATE OVER THE REGION...JUST TO THE SOUTH. MOISTURE WILL NOT BE A LIMITATION WITH PWATS PROGGED AROUND 2 INCHES (+1 STD DEV) AND DEWPOINTS IN THE MID-UPPER 60S. ANTICIPATE A DIURNAL TREND WITH SHOWERS/THUNDERSTORMS...BUT UPSTREAM MCS DEVELOPMENT MAY SPILL INTO THE REGION DURING THE OVERNIGHT HOURS THRU THE WEEKEND. HIGHER POPS MAY BE WARRANTED...BUT BASED ON THE DEGREE OF UNCERTAINTY AND TIMING...WILL STICK MORE TO CLIMO WITH CHANCE POPS DURING THE AFTERNOON AND EVENING. COULD BEGIN TO SEE A DRYING TREND BY LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS THE UPPER HIGH BUILDS EWD...SHUNTING THE BEST MOISTURE OFFSHORE. WITH THE LATEST MODEL RUNS PLACING THE FRONT SOUTH OF THE LOCAL AREA...NLY FLOW AND FALLING THICKNESSES WILL LIKELY YIELD TEMPS IN THE LOW-MID 80S. LOW-MID 80S TO CONTINUE THRU THE WEEKEND...WARMING BACK INTO THE MID 80S BY EARLY NEXT WEEK. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... A COMPLEX AREA OF LOW PRESSURE AND FRONTAL SYSTEMS COVERED THE MID ATLANTIC STATES MONDAY EVENING. LOW PRESSURE MOVES OFF THE COAST TUESDAY MORNING WITH WEAK HIGH PRESSURE BUILDING FROM THE NORTH THROUGH WEDNESDAY. UNSETTLED WEATHER RETURNS LATE IN THE WEEK. THE LINE OF TSTMS THAT AFFECTED SOUTHEAST VIRGINIA MOVED OFF THE COAST JUST PRIOR TO THE 00Z TAF ISSUANCE MORE SHOWERS WERE DEVELOPING BUT NO SIGNIFICANT TSTMS ARE EXPECTED OVERNIGHT. WITH MOIST CONDITIONS... MVFR WITH AREAS OF IFR CAN BE EXPECTED IN THE LATE EVENING AND OVERNIGHT. MVFR SHOULD END BY LATE MORNING. WIDELY SCT SHOWERS AND TSTMS WILL BE PSBL TUESDAY BUT NOT NEARLY AS WIDESPREAD AS THEY WERE MONDAY. OUTLOOK...SCT AFTN/EVENING TSTMS RETURN TO THE FCST THURSDAY THROUGH SATURDAY. THERE WILL BE THE POSSIBILITY OF MVFR/IFR CONDS WITHIN A FEW HOURS OF SUNRISE EACH MORNING. && .MARINE... UNSETTLED WEATHER PATTERN WILL PREVAIL OVER THE WATERS THRU THE FORECAST PERIOD...BUT SCA CONDITIONS ARE NOT ANTICIPATED. AREA OF LOW PRESSURE HAS LOCATED OVER WV WITH A FRONTAL BOUNDARY EXTENDING EWD OVER SRN VA AND THE LOWER BAY. MEANWHILE...HIGH PRESSURE BUILDS OVER THE NE STATES. THE RESULT IS GENERALLY ONSHORE AROUND 10 KT. WAVES/SEAS AVG 1-2 FT. SFC LOW WEAKENS OVER THE CNTRL APPALACHIANS AS AN ADDITIONAL AREA OF LOW PRESSURE DEVELOPS OVER THE WATERS. WITH THE SFC LOW OVER THE WATERS...FLOW OVER THE COASTAL WATERS (ON THE ERN PERIPHERY OF THE LOW) WILL BE SW OVER THE SRN WATERS...VEERING TO E OVER THE NRN WATERS...AVG 10-15 KT. SCA CONDITIONS ARE NOT ANTICIPATED. SEAS WILL BUILD ONLY TO 2-3 FT WITH WAVES AVG 1-2 FT. SFC LOW SLOWLY PUSHES OFFSHORE LATE TUES-TUES NIGHT AS HIGH PRESSURE OFF THE NE COAST RIDGES SWD OVER THE NRN WATERS. FLOW REMAINS GENERALLY ONSHORE...AOB 15 KT. LOW PRESSURE LINGERS OFF THE MID-ATLANTIC COAST THRU THE END OF THE WORK WEEK AND INTO THE WEEKEND AS A FRONTAL BOUNDARY REMAINS SOUTH OF THE WATERS. THE RESULT WILL BE ONGOING ONSHORE/NELY FLOW. GRADIENT WILL REMAIN WEAK (AOB 15 KT)...BUT PERSISTENT NE FETCH MAY PUSH SEAS UPWARDS OF 5 FT IN THE NRN COASTAL WATERS FRIDAY NIGHT THRU THE WEEKEND. UNDERCUT WAVEWATCH AS GFS IS NOT THE PREFERRED MEDIUM RANGE MODEL. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...ESS NEAR TERM...ESS/JAO SHORT TERM...ESS LONG TERM...SAM AVIATION...LSA MARINE...SAM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1141 PM EDT MON AUG 18 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 345 PM EDT MON AUG 18 2014 THE REGION IS HEADING INTO A WETTER PATTERN THE NEXT WEEK WITH THE FIRST CHANCES FOR RAINFALL COMING UP TONIGHT INTO TUESDAY. ANOTHER TIME FRAME OF PERIODS OF SHOWERS AND STORMS WILL COME FROM THURSDAY THROUGH SUNDAY WITH A FRONTAL BOUNDARY NEAR THE AREA. SHOWERS AND STORMS WILL BECOME MORE NUMEROUS LATE TONIGHT AND ESPECIALLY ON TUESDAY AS AN AREA OF LOW PRESSURE MOVES INTO THE GREAT LAKES. A GRADUAL WARMING TREND WILL BE SEEN THROUGH THE WEEK AND INTO NEXT WEEKEND. HIGHS AROUND 80 AT THE START OF THE WEEK WILL WARM TO THE MIDDLE 80S BY NEXT WEEKEND. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 345 PM EDT MON AUG 18 2014 MAIN FOCUS IN THE SHORT TERM IS ON THE CHANCES FOR SHOWERS/STORMS TONIGHT INTO TUESDAY. PRECIPITATION WILL BE DRIVEN BY AN TROUGH DIGGING INTO THE GREAT LAKES REGION FROM THE NORTHERN PLAINS. MOISTURE SURGES INTO REGION THIS EVENING WITH THE HRRR TRYING TO FLOAT CONVECTION FROM WISCONSIN OVER LAKE MICHIGAN IN THE 00Z-06Z TIME FRAME. THINKING OUR BEST CHANCES FOR PRECIP THOUGH WILL BE OVERNIGHT INTO TUESDAY WHEN ALL OF THE SHORT TERM MODELS FOCUS A LLJ ON THE AREA. NOT EXPECTING SEVERE WEATHER GIVEN THE TIMING OF THE PRECIP AND THE FACT THAT INSTABILITY WILL LIKELY BE LIMITED SOMEWHAT BY OVERNIGHT PRECIP. 0-6KM SHEAR IS SUB 30 KNOTS BOTH TONIGHT AND TUESDAY FOR THE MOST PART AS WELL. SOME LOCALLY HEAVY RAIN IS POSSIBLE. SHOWERS AND STORMS WILL BECOME MORE SCATTERED TUESDAY NIGHT THROUGH WEDNESDAY AS THE SYSTEM FILLS OVERHEAD. PLENTY OF MOISTURE LINGERS HOWEVER SO SCATTERED SHOWERS AND A FEW STORMS WILL REMAIN POSSIBLE BOTH PERIODS. WEDNESDAY NIGHT KEPT THE DRY FORECAST GOING AS SURFACE RIDGING BEGINS TO TAKE OVER AND THE UPPER LOW SLIDES SLIGHTLY OFF TO THE EAST. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 345 PM EDT MON AUG 18 2014 IT LOOKS TO BE A RATHER ACTIVE EXTENDED PERIOD. THE MAIN FOCUS WILL BE ON OPPORTUNITIES FOR SHOWERS AND STORMS THURSDAY THROUGH SUNDAY NIGHT. BY 12Z THURSDAY...A ULJ CORE WILL BE MOVING ACROSS THE LOWER PENINSULA AS UPPER LEVEL RIDGING BUILDINGS IN. IN CONCERT WITH THIS WILL BE A FAIRLY STRONG H850 TEMP GRADIENT (6-8C) MOVING INTO SW LOWER MICHIGAN AND INCREASING MID LEVEL MOISTURE. LIGHT EASTERLY WIND CONV AT THE SFC (AS SHOWN BY THE ECMWF) MAY HELP ENHANCE CONVECTIVE DEVELOPMENT PARTICULARLY ACROSS THE LAKESHORE REGION AND GENERALLY ALONG AND WEST OF US 131 FOR THURSDAY EVENING INTO FRIDAY. WHILE MODEL QPF IS NOT HIGH...INCREASING PW VALUES TO 2" OR SO ON FRIDAY IS A CAUSE FOR CONCERN WITH ANY STORMS THAT DO DEVELOP. LOCALLY HEAVY DOWNPOURS WOULD BE A POSSIBILITY THURSDAY NIGHT AND FRIDAY ON THE WING OF WARM AIR ADVECTION. IF H500 HEIGHTS CONTINUE TO BUILD STRONG ENOUGH BY SATURDAY (LIKE THE ECMWF SHOWS) THEN PERHAPS WE WILL BE STABLE ENOUGH TO MITIGATE ANY SIGNIFICANT CONVECTION. ON SATURDAY...GFS BUFKIT SOUNDINGS INDICATE SIGNIFICANT SFC BASED CAPE UPWARDS OF 2000 J/KG AND LI VALUES OF -4 TO -6 BUT WEAK SHEAR AND WEAK MID LEVEL LAPSE RATES. ECMWF WOULD SUGGEST A LACK OF TRIGGER AND MORE STABLE CONDITIONS. OUR POP GRIDS ARE CURRENTLY MIDDLE OF THE ROAD CHC CATEGORY FOR SATURDAY...REFLECTING A LACK OF MODEL BULLISHNESS ON PRECIP. UPPER LEVEL RIDGING MAY FLATTEN LATER SUNDAY AND AN ASSOCIATED COLD FRONT COULD ARRIVE BY SUNDAY NIGHT. THE TIMING OF THIS IS ACTUALLY AGREED UPON BY THE GFS AND ECMWF (00Z-06Z MON)...WHEREAS THE GEM CLEARS THE FRONT 24 HOURS EARLIER. CURRENTLY AM PREFERRING A SLOWER BREAKDOWN OF THE H500 RIDGE AND THUS A SLOWER FROPA AS SHOWN BY THE GFS AND ECMWF. THERE WILL LIKELY BE SUFFICIENT DEEP LAYER SHEAR BY THAT TIME TO PROVIDE A MORE CONDUCIVE ENVIRONMENT TO STRONGER STORMS. IN TERMS OF TEMPS AND HUMIDITY...BOTH WILL BE GOING UP BY THE WEEKEND. DEW POINTS SHOULD CLIMB TO AROUND 70 AND HIGHS IN THE MID 80S MAY BE CONSERVATIVE FOR SATURDAY AND SUNDAY DEPENDING ON MUCH CLOUD COVER HANGS AROUND. WOULDN`T BE SURPRISED IF HIGHS NOTCH UP SEVERAL DEGREES WARMER WITH H850 TEMPS OF 20C KNOCKING ON THE DOOR SATURDAY EVENING. COOLER WEATHER MOVES IN FOR EARLY NEXT WEEK BEHIND THE FRONT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1137 PM EDT MON AUG 18 2014 AREA OF THUNDERSTORMS WILL BE CROSSING PARTS OF SOUTHWEST LOWER MI TO START THE PERIOD. THERE COULD BE LOCAL IFR WITHIN THIS AREA OF RAIN. THUNDERSTORMS WILL REDEVELOP ON TUESDAY...ESPECIALLY INLAND. INCREASING MOISTURE WILL ALSO LEAD TO HAZY CONDITIONS. MVFR LIKELY FOR MANY LOCATIONS...BUT ANY THUNDERSTORM WILL BE CAPABLE OF LOCAL IFR OR LOWER. && .MARINE... ISSUED AT 345 PM EDT MON AUG 18 2014 MAIN IMPACT WEATHER FOR WINDS/WAVES WILL COME ON TUESDAY. SOUTH WINDS WILL INCREASE TONIGHT INTO TUESDAY WITH WAVES BECOMING BORDERLINE FOR BEACH HAZARDS FROM HOLLAND NORTHWARD UP THE SHORE. EXPECTING WAVES TO PUSH INTO THE 2 TO 4 FOOT RANGE ON TUESDAY NORTH OF HOLLAND OR SO. THE WINDS SLACKEN OFF AS WE HEAD INTO WEDNESDAY AS THE GRADIENT BECOMES BAGGY...SO THE WAVES WILL SUBSIDE FOR MID WEEK. && .HYDROLOGY... ISSUED AT 139 PM EDT MON AUG 18 2014 RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW BANK FULL. PRECIPITATION THIS EVENING THROUGH WEDNESDAY IS EXPECTED TO TOTAL AROUND HALF AN INCH. THIS SHOULD LEAD TO SLOW RISES ON AREA RIVERS WITH PEAK LEVELS WELL BELOW FLOOD STAGE OCCURRING BY THE END OF THE WEEK. LOCALLY HEAVY RAINFALL IS POSSIBLE AND COULD LEAD TO BRIEFLY HIGHER FLOWS. LOOKING AHEAD...IT APPEARS TO BE A RATHER ACTIVE SECOND HALF OF AUGUST WHICH MAY HELP BRING MANY RIVERS TO ABOVE NORMAL FLOWS. WITH AN UPPER LEVEL RIDGE DEVELOPING TO THE SOUTH OF THE GREAT LAKES OVER THE NEXT WEEK OR SO...IT WILL PLACE MICHIGAN IN AN ACTIVE WEATHER PATTERN WITH NUMEROUS OPPORTUNITIES FOR RAIN. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...DUKE SHORT TERM...DUKE LONG TERM...HOVING AVIATION...MJS HYDROLOGY...63 MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
806 PM EDT MON AUG 18 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 345 PM EDT MON AUG 18 2014 THE REGION IS HEADING INTO A WETTER PATTERN THE NEXT WEEK WITH THE FIRST CHANCES FOR RAINFALL COMING UP TONIGHT INTO TUESDAY. ANOTHER TIME FRAME OF PERIODS OF SHOWERS AND STORMS WILL COME FROM THURSDAY THROUGH SUNDAY WITH A FRONTAL BOUNDARY NEAR THE AREA. SHOWERS AND STORMS WILL BECOME MORE NUMEROUS LATE TONIGHT AND ESPECIALLY ON TUESDAY AS AN AREA OF LOW PRESSURE MOVES INTO THE GREAT LAKES. A GRADUAL WARMING TREND WILL BE SEEN THROUGH THE WEEK AND INTO NEXT WEEKEND. HIGHS AROUND 80 AT THE START OF THE WEEK WILL WARM TO THE MIDDLE 80S BY NEXT WEEKEND. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 345 PM EDT MON AUG 18 2014 MAIN FOCUS IN THE SHORT TERM IS ON THE CHANCES FOR SHOWERS/STORMS TONIGHT INTO TUESDAY. PRECIPITATION WILL BE DRIVEN BY AN TROUGH DIGGING INTO THE GREAT LAKES REGION FROM THE NORTHERN PLAINS. MOISTURE SURGES INTO REGION THIS EVENING WITH THE HRRR TRYING TO FLOAT CONVECTION FROM WISCONSIN OVER LAKE MICHIGAN IN THE 00Z-06Z TIME FRAME. THINKING OUR BEST CHANCES FOR PRECIP THOUGH WILL BE OVERNIGHT INTO TUESDAY WHEN ALL OF THE SHORT TERM MODELS FOCUS A LLJ ON THE AREA. NOT EXPECTING SEVERE WEATHER GIVEN THE TIMING OF THE PRECIP AND THE FACT THAT INSTABILITY WILL LIKELY BE LIMITED SOMEWHAT BY OVERNIGHT PRECIP. 0-6KM SHEAR IS SUB 30 KNOTS BOTH TONIGHT AND TUESDAY FOR THE MOST PART AS WELL. SOME LOCALLY HEAVY RAIN IS POSSIBLE. SHOWERS AND STORMS WILL BECOME MORE SCATTERED TUESDAY NIGHT THROUGH WEDNESDAY AS THE SYSTEM FILLS OVERHEAD. PLENTY OF MOISTURE LINGERS HOWEVER SO SCATTERED SHOWERS AND A FEW STORMS WILL REMAIN POSSIBLE BOTH PERIODS. WEDNESDAY NIGHT KEPT THE DRY FORECAST GOING AS SURFACE RIDGING BEGINS TO TAKE OVER AND THE UPPER LOW SLIDES SLIGHTLY OFF TO THE EAST. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 345 PM EDT MON AUG 18 2014 IT LOOKS TO BE A RATHER ACTIVE EXTENDED PERIOD. THE MAIN FOCUS WILL BE ON OPPORTUNITIES FOR SHOWERS AND STORMS THURSDAY THROUGH SUNDAY NIGHT. BY 12Z THURSDAY...A ULJ CORE WILL BE MOVING ACROSS THE LOWER PENINSULA AS UPPER LEVEL RIDGING BUILDINGS IN. IN CONCERT WITH THIS WILL BE A FAIRLY STRONG H850 TEMP GRADIENT (6-8C) MOVING INTO SW LOWER MICHIGAN AND INCREASING MID LEVEL MOISTURE. LIGHT EASTERLY WIND CONV AT THE SFC (AS SHOWN BY THE ECMWF) MAY HELP ENHANCE CONVECTIVE DEVELOPMENT PARTICULARLY ACROSS THE LAKESHORE REGION AND GENERALLY ALONG AND WEST OF US 131 FOR THURSDAY EVENING INTO FRIDAY. WHILE MODEL QPF IS NOT HIGH...INCREASING PW VALUES TO 2" OR SO ON FRIDAY IS A CAUSE FOR CONCERN WITH ANY STORMS THAT DO DEVELOP. LOCALLY HEAVY DOWNPOURS WOULD BE A POSSIBILITY THURSDAY NIGHT AND FRIDAY ON THE WING OF WARM AIR ADVECTION. IF H500 HEIGHTS CONTINUE TO BUILD STRONG ENOUGH BY SATURDAY (LIKE THE ECMWF SHOWS) THEN PERHAPS WE WILL BE STABLE ENOUGH TO MITIGATE ANY SIGNIFICANT CONVECTION. ON SATURDAY...GFS BUFKIT SOUNDINGS INDICATE SIGNIFICANT SFC BASED CAPE UPWARDS OF 2000 J/KG AND LI VALUES OF -4 TO -6 BUT WEAK SHEAR AND WEAK MID LEVEL LAPSE RATES. ECMWF WOULD SUGGEST A LACK OF TRIGGER AND MORE STABLE CONDITIONS. OUR POP GRIDS ARE CURRENTLY MIDDLE OF THE ROAD CHC CATEGORY FOR SATURDAY...REFLECTING A LACK OF MODEL BULLISHNESS ON PRECIP. UPPER LEVEL RIDGING MAY FLATTEN LATER SUNDAY AND AN ASSOCIATED COLD FRONT COULD ARRIVE BY SUNDAY NIGHT. THE TIMING OF THIS IS ACTUALLY AGREED UPON BY THE GFS AND ECMWF (00Z-06Z MON)...WHEREAS THE GEM CLEARS THE FRONT 24 HOURS EARLIER. CURRENTLY AM PREFERRING A SLOWER BREAKDOWN OF THE H500 RIDGE AND THUS A SLOWER FROPA AS SHOWN BY THE GFS AND ECMWF. THERE WILL LIKELY BE SUFFICIENT DEEP LAYER SHEAR BY THAT TIME TO PROVIDE A MORE CONDUCIVE ENVIRONMENT TO STRONGER STORMS. IN TERMS OF TEMPS AND HUMIDITY...BOTH WILL BE GOING UP BY THE WEEKEND. DEW POINTS SHOULD CLIMB TO AROUND 70 AND HIGHS IN THE MID 80S MAY BE CONSERVATIVE FOR SATURDAY AND SUNDAY DEPENDING ON MUCH CLOUD COVER HANGS AROUND. WOULDN`T BE SURPRISED IF HIGHS NOTCH UP SEVERAL DEGREES WARMER WITH H850 TEMPS OF 20C KNOCKING ON THE DOOR SATURDAY EVENING. COOLER WEATHER MOVES IN FOR EARLY NEXT WEEK BEHIND THE FRONT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 805 PM EDT MON AUG 18 2014 VFR CONDITIONS ARE EXPECTED TO DETERIORATE TO MVFR AROUND 05Z OR SO. AS OF THIS WRITING...THE LEADING EDGE OF A LINE SHOWERS AND WEAKENING THUNDERSTORMS OVER CENTRAL WISCONSIN IS MAKING ITS WAY ACROSS NORTHERN LAKE MICHIGAN. THESE STORMS ARE EXPECTED TO CONTINUE TO COLLAPSE AS THEY MOVE ESE TOWARD KLDM. HIGHER IMPACTS ARE EXPECTED AFTER ROUGHLY 10Z AND CONTINUING THROUGH THE MORNING FOR ALL TAF SITES. MORE WIDESPREAD SHOWERS AND STORMS WILL MOVE IN AND WINDS WILL INCREASE TO AROUND 10-12 KTS OUT OF THE SOUTH. SCATTERED IFR CERTAINLY A POSSIBILITY UNDER HEAVIER PRECIPITATION. CONFIDENCE IN IFR IS AVERAGE AND FUTURE AMENDMENTS AND ISSUANCES MAY LOWER VSBYS/CIGS. CONDITIONS WILL GRADUALLY IMPROVE AFTER 18Z TUESDAY. && .MARINE... ISSUED AT 345 PM EDT MON AUG 18 2014 MAIN IMPACT WEATHER FOR WINDS/WAVES WILL COME ON TUESDAY. SOUTH WINDS WILL INCREASE TONIGHT INTO TUESDAY WITH WAVES BECOMING BORDERLINE FOR BEACH HAZARDS FROM HOLLAND NORTHWARD UP THE SHORE. EXPECTING WAVES TO PUSH INTO THE 2 TO 4 FOOT RANGE ON TUESDAY NORTH OF HOLLAND OR SO. THE WINDS SLACKEN OFF AS WE HEAD INTO WEDNESDAY AS THE GRADIENT BECOMES BAGGY...SO THE WAVES WILL SUBSIDE FOR MID WEEK. && .HYDROLOGY... ISSUED AT 139 PM EDT MON AUG 18 2014 RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW BANK FULL. PRECIPITATION THIS EVENING THROUGH WEDNESDAY IS EXPECTED TO TOTAL AROUND HALF AN INCH. THIS SHOULD LEAD TO SLOW RISES ON AREA RIVERS WITH PEAK LEVELS WELL BELOW FLOOD STAGE OCCURRING BY THE END OF THE WEEK. LOCALLY HEAVY RAINFALL IS POSSIBLE AND COULD LEAD TO BRIEFLY HIGHER FLOWS. LOOKING AHEAD...IT APPEARS TO BE A RATHER ACTIVE SECOND HALF OF AUGUST WHICH MAY HELP BRING MANY RIVERS TO ABOVE NORMAL FLOWS. WITH AN UPPER LEVEL RIDGE DEVELOPING TO THE SOUTH OF THE GREAT LAKES OVER THE NEXT WEEK OR SO...IT WILL PLACE MICHIGAN IN AN ACTIVE WEATHER PATTERN WITH NUMEROUS OPPORTUNITIES FOR RAIN. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...DUKE SHORT TERM...DUKE LONG TERM...HOVING AVIATION...EBW HYDROLOGY...63 MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
743 PM EDT MON AUG 18 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 322 PM EDT MON AUG 18 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A FAIRLY STRONG SHRTWV OVER THE NRN PLAINS DRIFTING TO THE ESE INTO NW MN DOWNSTREAM OF A RDG OVER WRN CANADA AND TOWARD A SHRTWV RDG STRETCHING FM HUDSON BAY TOWARD THE SE GREAT LKS ON THE WRN FLANK OF A DEEP TROF OVER THE CNDN MARITIMES. THERE IS ALSO A WEAKER SHRTWV MOVING E THRU THE UPR LKS AHEAD OF THE MAIN DISTURBANCE APRCHG MN...AND THIS FEATURE ALONG WITH ACCOMPANING AXIS OF GREATER H85 THETA E ADVCTN/A FAIRLY MOIST 12Z GRB RAOB /KINX 36C AND PWAT 1.64 INCH OR ALMOST 175 PERCENT OF NORMAL/ HAS BEEN THE FOCUS FOR SOME SCT-NMRS SHOWERS MAINLY OVER CENTRAL CWA TODAY. BUT QUITE A CONTRAST JUST TO THE E WITH THE 12Z APX RAOB DISPLAYING A MUCH DRIER PROFILE...KINX -12C AND PWAT 0.66 INCH OR ONLY 75 PERCENT OF NORMAL. THIS DRIER/STABLE AIRMASS HAS SLOWED THE PROGRESS OF THE SHOWERS INTO THE AREA ARND NEWBERRY SO FAR. THERE ARE MORE NMRS SHOWERS/A FEW TS MOVING INTO WRN LK SUP CLOSER TO THE TRAILING SHRTWV. OTRW...QUITE A BIT OF CLD COVER HAS LIMITED THE DIURNAL RISE OF TEMP AND DESTABILIZATION IN THE ABSENCE OF STEEP LAPSE RATES SHOWN ON EVEN THE MOISTER 12Z GRB RAOB...SO TS HAVE BEEN FEW AND FAR BTWN. BUT SOME HEAVY RAINS HAVE FALLEN UNDER THE STRONGER SHOWERS WITH THE HIER PWAT/DEEPER MSTR. MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS RELATED TO THE TWO DISTURBANCES THAT ARE MOVING THRU MN/THE UPR LKS. LATE TODAY/TNGT...AS TROF OVER QUEBEC SLOWLY EXITS TO THE E...LEAD SHRTWV MOVING THRU THE UPR LKS/ACCOMPANYING AXIS OF H85 THETA E ADVCTN WL DRIFT TO THE E AND BRING SOME SHOWERS TO THE FAR ERN CWA BY 00Z. ALTHOUGH THERE MAY BE ONLY SOME ISOLD/SCT SHOWERS OVER WRN UPR MI WITH SOME H7-5 DRYING MOST OF TODAY...MORE NMRS SHOWERS/SOME TS ASSOCIATED WITH THE STRONGER SHRTWV MOVING INTO MN WL ARRIVE OVER THE FAR W ARND 00Z TOWARD AREA WHERE THE 12Z NAM/REGIONAL CNDN MODEL SHOW HIER MUCAPE UP TO ABOUT 750 J/KG NEAR IWD. BUT SINCE THE MN SHRTWV WL BE TENDING TO DIG ESEWD THRU THE NGT...THE 12Z NAM/ REGIONAL CNDN MODEL INDICATE THE MORE NMRS SHOWERS WL IMPACT WI CLOSER TO MORE VIGOROUS H85-7 MSTR CNVGC/HIER MUCAPE IN THE 500- 1000J/KG THAT WL BE CONFINED TO WI. SO WL MAINTAIN THE HIEST LIKELY POPS TOWARD THE WI BORDER... ALONG WITH THE TS CHANCES PER ABSENCE OF FCST MUCAPE AOA 200 J/KG FARTHER N. BUT DEEP LYR QVECTOR CNVGC/ DEEP SATURATION ON FCST SDNGS ON THE CYC SIDE OF SHRTWV TRACK JUSTIFIES AT LEAST 50-60 POPS OVER THE ENTIRE CWA EVEN IF THE BETTER FORCING/INSTABILITY HOLD TO THE SW. EXPECT LTL DIURNAL TEMP DROP WITH LOTS OF CLDS/LINGERING HIER PWAT IN THE 1.50-1.75 RANGE. ADDED SOME PATCHY FOG...ESPECIALLY IN AREAS OVER THE CENTRAL THAT WL EXPERIENCE UPSLOPE SE FLOW. TUE...EXPECT CONTINUED SCT-NMRS SHOWERS AND A FEW TS AS THE SHRTWV/ SFC LO REFLECTION SLIDE ESEWD THRU NRN WI AND MAINTAINS DEEP MSTR... CYC FLOW AND DEEP LYR QVECTOR CNVGC OVER UPR MI. FCST WL SHOW DIMINISHING POPS IN THE AFTN OVER THE W WITH PASSAGE OF SHRTWV TO THE E AND ARRIVAL OF SOME DNVA/DEEP LYR QVECTOR DVGC AFT 18Z. FOG IN THE MRNG OVER MAINLY THE CENTRAL ZNS WL DSPT SLOWLY WITH DIURNAL HEATING LIMITED BY EXTENSIVE CLD COVER. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 431 PM EDT MON AUG 18 2014 THE 500MB LOW CENTERED OVER UPPER MI AND LAKE SUPERIOR AT 00Z WEDNESDAY WILL SHIFT ACROSS LAKE HURON WEDNESDAY NIGHT/THURSDAY MORNING WITH A BRIEF RIDGE BUILDING ACROSS UPPER MI THURSDAY. THE APEX OF THE RIDGE WILL SHIFT JUST TO OUR E THURSDAY NIGHT. A SIZABLE TROUGH SET UP FROM FROM W AND CENTRAL CANADA THROUGH THE ENTIRE W U.S. WEDNESDAY WILL SLOWLY SHIFT THE N CENTRAL U.S. FOR THE WEEKEND...AND UPPER GREAT LAKES SUNDAY NIGHT/MONDAY. AS FOR THE SFC FEATURES AND WX...THE EXITING SFC LOW OVER N LAKE MI AT 00Z WEDNESDAY WILL LINGER THROUGH THE NIGHT BEFORE SHIFTING TO LOWER MI THROUGH THE DAY WEDNESDAY. WITH WRAP AROUND/UPSLOPE MOISTURE ACROSS THE AREA...EXPECT LIGHT SHOWERS TO LINGER THROUGH MID DAY AT LEAST. THE BEST CHANCE OF THUNDERSTORMS WILL SINK SE WITH THE SFC LOW. IT LOOKS LIKE THE ONLY PERIOD OF MAINLY DRY WEATHER WILL BE LATE WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING...DESPITE THE 500MB RIDGE OVERHEAD THURSDAY THROUGH FRIDAY. THE LARGE HIGH PRESSURE OVER QUEBEC...WITH A RIDGE EXTENDING OVER THE UPPER GREAT LAKES WILL EXIT E ON FRIDAY. THERE STILL LOOKS TO BE PLENTY OF INCONSISTENCIES FOR FRIDAY AFTERNOON ON. WILL CONTINUE TO RUN WITH A GENERAL CONSENSUS FOR THIS PERIOD...WITH HAS AN ELONGATED SFC LOW FROM HUDSON BAY THROUGH MN AND THE CENTRAL PLAINS AT 00Z SUNDAY. THE LOW WILL SLOWLY SHIFT TO ONTARIO/FAR W LAKE SUPERIOR SATURDAY. THIS WOULD BRING WAA TO THE AREA WITH HIGH TEMPS RETURNING TO NEAR NORMAL READINGS FRIDAY AND SATURDAY. THE SFC TROUGH SHOULD BE OVER THE CWA SATURDAY NIGHT/SUNDAY MORNING. HAVE SLOWLY DIMINISHING POPS FOR SUNDAY AND MONDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 742 PM EDT MON AUG 18 2014 ALTHOUGH THE SPECIFICS ARE UNCERTAIN...LIFR TO POSSIBLY VLIFR CONDITIONS WILL LIKELY PREVAIL AT KCMX/KSAW THRU AT LEAST TUE MORNING UNDER LIGHT UPSLOPE FLOW/DEEP MOISTURE AND SCT TO AT TIMES NMRS SHRA ASSOCIATED WITH DISTURBANCE MOVING SLOWLY ESEWD THRU MN. AT KIWD...LOW-LEVEL MOISTURE HAS MIXED OUT TEMPORARILY...AND THIS SHOULD ALLOW VFR CONDITIONS FOR THE NEXT FEW HRS...THOUGH OCCASIONALLY MVFR AS SCT SHRA IN NW WI SPREAD E AND NE. EXPECT A RETURN TO IFR LATE EVENING AND THEN TO LIFR LATE TONIGHT AS WINDS BECOME LIGHT UPSLOPE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 322 PM EDT MON AUG 18 2014 ADDED SOME FOG TO THE FORECAST THRU MUCH OF TUE OVER MAINLY THE CENTRAL LAKE GIVEN ARRIVAL OF DEEPER MOISTURE AND EXPECTED AREA OF LOWER TEMPERATURES NEAR THE LINGERING COOLEST DEEPER WATER. OTHERWISE... EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
334 PM EDT SUN AUG 17 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 332 PM EDT SUN AUG 17 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL... WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9 ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY THIS AFTN. MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS. TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS ARE THE CONCERNS FOR LATER TNGT AND MON. LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO THE CROSS OVER DEWPTS OBSVD THIS AFTN. MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE 60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE INCOMING DISTURBANCE/COLDER AIR ALF. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 332 PM EDT SUN AUG 17 2014 AT 00Z TUESDAY THE NEXT 500MB WAVE WILL BE SET UP ACROSS MN THROUGH W ONTARIO. MID/LONG TERM MODELS INDICATE THAT THIS FEATURE WILL DEVELOP INTO A LOW 12-18Z TUESDAY OVER E MN AND THE W HALF OF THE MQT CWA. AT THAT POINT...LITTLE MOVEMENT WILL BE EXPECTED AT 500MB UNTIL AFTER DAYBREAK WEDNESDAY...AS THE 500MB SITS AND SPINS ACROSS UPPER MI AND LAKE SUPERIOR. THE SFC LOW SHOULD TRACK FROM N AND CENTRAL MN AT 00Z TUESDAY NEAR THE WI/UPPER MI BORDER ON TUESDAY...BEFORE EXITING ACROSS LAKE MI TUESDAY NIGHT...AND LOWER MI ON WEDNESDAY. WITH UPPER MI STAYING ON THE N SIDE OF THE SFC LOW EXPECT A PERIOD OF CLOUDY CONDITIONS...WITH AFTERNOON TEMPS ON TUESDAY AVERAGING AROUND 5F BELOW THE SEASONAL NORMAL VALUES. THE BEST CHANCE FOR PRECIP IS DIFFICULT TO PIN DOWN AT THIS POINT...AS FCST MODELS VARY SIGNIFICANTLY WITH THE SMALLER SCALE FEATURES WITH THIS DEVELOPING SYSTEM. WILL CONTINUE TO GO RELATIVELY GENERAL WITH THE POPS AT THIS POINT. WILL KEEP TS POTENTIAL TO A MINIMUM...GIVEN THE TRACK OF THE SFC LOW MAINLY TO OUR S...AND MU CAPE VALUES OVER THE FAR W AOB 100J/KG FAR W TUESDAY MORNING. TUESDAY DURING THE DAY DOESN/T LOOK MUCH MORE IMPRESSIVE...TOPPING OUT ALONG THE WI BORDER GENERALLY AROUND 200 J/KG OR LESS /RESTRICTED TS MENTION TO CENTRAL U.P./. THE 500MB RIDGE WILL BRIEFLY BUILD OVERHEAD LATER WEDNESDAY INTO EARLY THURSDAY. OUT OF THE WORK WEEK FROM TUESDAY ON...THIS SHOULD BE THE DRIEST PERIOD. WILL TRY TO SHOW A BIT MORE IN OUR FCST...DESPITE THE PW VALUES REMAINING 80-140 PERCENT OF NORMAL /LOWEST E/. THE CHANCE OF SHOWERS RETURN LATE THURSDAY INTO FRIDAY AS A SHORTWAVE/TROUGH GLANCES THE AREA. TS MAY RETURN ON FRIDAY. EXPECT WAA FRIDAY TO PUSH 850MB TEMPS UP TO 15-19C. IF CLOUDS AND PRECIP CAN STAY TO A MINIMUM...SFC SHOULD SHIFT TO ABOVE NORMAL READINGS. AS FOR THE OPEN HOUSE AT THE MQT NWS ON SATURDAY 10AM-2PM EDT...THERE IS ENOUGH DISCREPANCIES AT THIS POINT IN THE FCST MODEL DATA TO KEEP A GENERAL BLEND OR CONSENSUS GOING. BOTH THE GFS AND ECMWF SHOW A 500MB LOW TO THE W OF UPPER MI AT 12Z. HOWEVER...LOCATIONS VARY FROM N MANITOBA TO THE DAKOTAS...WITH A SFC LOW OR TROUGH EITHER JUST TO OUR W OR OVER W UPPER MI. IF THE 17/00Z AND 06Z GFS RUNS ARE CORRECT...WINDS NEAR 20KTS WILL BE POSSIBLE. THE 12Z RUN DID DIMINISH THESE STRONG WINDS...DOWN TO AROUND 10KTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 123 PM EDT SUN AUG 17 2014 WITH DAYTIME HEATING/DRY AIR SLOWLY ENCROACHING FM THE NE TO THE S OF HI PRES MOVING INTO NRN LK SUP...EXPECT LO CLDS/MVFR CIGS IMPACTING THE TAF SITES TO GIVE WAY TO CLRG/VFR CONSITIONS THRU THE AFTN. MORE CLDS AND EVEN A FEW -SHRA IN ADVANCE OF DISTURBANCE SPREADING E FM MN WL ARRIVE OVER THE W OVERNGT. PER UPSTREAM OBS IN MN...FCST MVFR CIGS TO ARRIVE AT IWD AND THEN CMX ON MON MRNG AS DEEPER MSTR ASSOCIATED WITH AN APRCHG DISTURBANCE OVERSPREADS THESE SITES. ALTHOUGH THIS DEEPER MSTR IS LIKELY TO REMAIN W OF SAW THRU THIS TAF PERIOD...SOME FOG MAY DVLP AT THAT SITE OVERNGT. DID NOT FCST A LOWER CONDITION ATTM WITH EXPECTATION THAT HI CLDS PUSHING E OF THE APRCHG DISTURBANCE MAY LIMIT DIURNAL COOLING SUFFICIENTLY TO PREVENT FOG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 332 PM EDT SUN AUG 17 2014 EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
100 AM EDT SUN AUG 17 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 407 PM EDT SAT AUG 16 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER QUEBEC WITH NW FLOW IN ITS WAKE THROUGH THE NRN GREAT LAKES. AT THE SFC...THE COLD FRONT HAS DROPPED SOUTH OF UPPER MI AS HIGH PRES OVER NRN MANITOBA INTO NW ONTARIO BUILDS SOUTHWARD. ALTHOUGH STRONG MID LEVEL DRYING HAD TAKEN OVER IN THE WAKE OF THE SHRTWV THAT MOVED THROUGH EARLY TODAY...ABUNDANT LOW LEVEL MOISTURE AND NRLY FLOW SUSTAINED OVC SKIES OVER MOST OF NRN UPPER MI. DOWNSLOPE FLOW AND DAYTIME MIXING HAS BROUGHT MORE CLEARING TO SRN UPPER MI. TONIGHT...HIGH PRES WILL BUILD FROM NRN ONTARIO THROUGH THE NRN GREAT LAKES. CLOUDS SHOULD CONTINUE TO DIMINISH THIS EVENING BUT WILL BE BE DELAYED WHERE ONSHORE/UPSLOPE NE WINDS PREVAIL...PER UPSTREAM/SATELLITE TRENDS AND NAM/RUC 925-900 MB RH FCST. WITH ENOUGH CLEARING MIN READINGS WILL FALL INTO THE MID 40S INLAND BUT WHERE THICKER CLOUDS PERSIST...LOWS WILL ONLY DROP INTO THE LOWER 50S. SUNDAY...AS THE RIDGE BUILDS OVER THE AREA...EXPECT THAT THE COMBINATION OF DRY ADVECTION AND MIXING BY AFTERNOON WILL FINALLY SCOUR OUT THE REMAINING OVERCAST WITH MAINLY JUST SCT/BKN CU INLAND. TEMPS WILL CLIMB BACK INTO EH UPPER 50S AND LOWER 70S BUT REMAIN IN THE LOWER 60S WHERE ENE ONSHORE FLOW PREVAILS NEAR LAKE SUPERIOR. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 PM EDT SAT AUG 16 2014 MAIN FCST CONCERNS IN THE LONGER TERM WL FOCUS ON HOW QUICKLY SHRTWV NOW TRACKING THRU THE NRN ROCKIES AND ACCOMPANYING DEEPER MSTR WL ARRIVE AND IMPACT POPS INTO MID WEEK UNDER BLDG UPR RDG. SUN NGT/MON...SFC HI PRES JUST S OF JAMES BAY UNDER RDG AXIS ACRS NW ONTARIO AT 12Z MON WL DOMINATE AND BRING DRY WX THRU AT LEAST MOST OF SUN NGT. BUT A GOOD NUMBER OF THE MORE RECENT MODELS HAVE TRENDED FASTER ON SHIFTING THE REMNANT OF THE CLOSED LO TRACKING THRU THE NRN ROCKIES/ASSOCIATED MSTR UNDER WAD IN ADVANCE OF THIS DISTURBANCE TO THE E AND TOWARD THE UPR LKS ON MON. SO HAVE INCREASED CLD COVER AND BROUGHT POPS TO THE E FASTER THAN SHOWN ON THE PREVIOUS FCST... WITH CHC POPS OVER THE W BY 12Z MON AND ACROSS ALL BUT THE E ON MON AFTN AS PWAT IS FCST TO INCRS TO 1.50 TO 1.75 INCHES UNDER FALLING HGTS/DIFFLUENT UPR FLOW/DPVA/DEEP LYR QVECTOR CNVGC TO THE E OF THE APRCHG SHRTWV. CONSIDERING THE FASTER ARRIVAL OF THE MSTR/STRONGER SLY FLOW FM THE W...BUMPED UP FCST MIN TEMPS OVER THE W ON SUN NGT. BUT LOWERED FCST TEMPS OVER THE INTERIOR E CLOSER TO THE DEPARTING SFC HI/DRIER AIR WITH PWAT UNDER 0.75 INCH/LIGHTER WINDS. WITH AN EARLIER ARRIVAL OF MORE CLDS ON MON...OPTED TO LOWER FCST HI TEMPS A BIT DESPITE FCST H85 TEMPS UP TO 14-15C OVER THE W. MON NGT INTO WED...WHILE MEAN UPR RDG IS FCST TO BUILD ACROSS ERN NAMERICA DOWNSTREAM OF DEEPENING TROF OVER THE W...SHRTWV APRCHG FM THE W WL DRIFT SLOWLY THRU THE GREAT LKS. UNDER POCKET OF COOLER H5 TEMPS/HIER PWAT UP TO 1.50-1.75 INCHES...THERE WL BE AT LEAST SOME SCT SHOWERS/A FEW TS ARND DURING THIS PERIOD. THE PROBABILITY OF THESE SHOWERS WL BE GREATEST DURING DAYTIME HEATING ON TUE AFTN/ EVNG. A GOOD DEAL OF CLD COVER WL RESTRICT THE DIURNAL TEMP RANGE...WITH HI TEMPS NOT FAR FM 70 RUNNING BLO NORMAL BUT MRNG LO TEMPS MAINLY 55 TO 60 ABV AVG. IF THE UPR LO EXITS FASTER ON WED... MORE AFTN SUNSHINE MIGHT ALLOW FOR WARMER TEMPS THEN. END OF THE WEEK...AS THE SHRTWV MOVING THRU THE LKS SHIFTS AWAY LATER WED AND HGTS RISE...EXPECT A DRYING TREND FOR WED NGT INTO THU. SOME OF THE LONGER RANGE GUIDANCE HINTS ANOTHER SHRTWV RIDING ENEWD THRU THE UPR MS RIVER VALLEY AND TOWARD NW ONTARIO/THE UPR LKS MAY BRING MORE SHOWERS/A FEW TS TO THE AREA LATER ON THU INTO FRI. VARIOUS MODELS INDICATE THIS SHRTWV WL BE SLOWER AND NOT IMPACT THE AREA UNTIL SAT. CONSIDERING THE UNCERTAINTY ON SPECIFICS THIS FAR OUT IN THE FCST PERIOD...WL RELY ON EXTENDED MODEL CONSENSUS FOR FCST GENERATION. OVERALL TEMPS SHOULD RUN AOA NORMAL IN THE PRESENCE OF MEAN UPR RDG TO THE E OF LARGER SCALE WRN TROF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1259 AM EDT SUN AUG 17 2014 LOW CLOUDS WILL BE THE MAIN CONCERN THRU THIS MORNING...MAINLY AT KCMX/KSAW. WITH A GENERAL DOWNSLOPE EASTERLY FLOW AT KIWD...NOTHING MORE THAN SCT LOW CLOUDS ARE EXPECTED. SO...VFR CONDITIONS SHOULD PREVAIL. SATELLITE IMAGERY CONTINUES TO SHOW LOW CLOUDS MOVING/DEVELOPING S AND AFFECTING KCMX/KSAW. THESE MVFR CIGS SHOULD PERSIST THRU THE NIGHT. EXACTLY WHEN THE CLOUDS WILL CLEAR OUT IS UNCERTAIN...BUT IMPROVEMENT TO VFR SHOULD OCCUR AT KCMX/KSAW NO LATER THAN LATE MORNING/EARLY AFTN AS FLOW BECOMES INCREASINGLY ANTICYCLONIC AND MOISTURE MIXES OUT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 335 PM EDT SAT AUG 16 2014 EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KC AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
329 PM CDT Sun Aug 17 2014 .SHORT TERM: (Through Late Tonight) Issued at 323 PM CDT Sun Aug 17 2014 Surface low/MCV continues to make very slow progress to the east southeast away from forecast area. Will still see some lingering light showers/sprinkles for far eastern and southeastern portions of forecast area this evening. Then begin to dry out with clouds scattering out a bit. Lows will be in the mid 60s to low 70s. Another issue tonight could be fog development. Will add mention of patchy fog after potential issue tonight could be fog...as boundary layer will remain very moist. Due to uncertainty in cloud cover overnight tonight...elected not add fog to forecast for now. Byrd .LONG TERM: (Monday through Next Sunday) Issued at 323 PM CDT Sun Aug 17 2014 Monday will remain dry but will see plenty of cu developing so temperatures will warm up but not as much as previously thought. Lowered highs a degree or two. Highs will be in the mid upper 80s. Next shortwave/cold front to move through region beginning Monday night. So kept chance pops going through Tuesday. Then system to stall out over southern portions of forecast area before returning north as a warm front beginning Tuesday night. Will see rain chances across most of area Tuesday night, then lift northward out of area by Thursday, though kept low chance pops going for northern portions of forecast area through Friday night. During this period, will see a warming trend, but did lower highs a tad on Tuesday due to warm front position as well as clouds and precipitation, in the mid 80s to low 90s. Then temps warm up into the 90s everywhere for the last half of the work week and into the first part of the weekend. With frontal boundary lingering just north of forecast area for the weekend, could see some activity in the northern portions of forecast area, but hard to pin down at this time. Byrd && .AVIATION: (For the 18z TAFs through 18z Monday Afternoon) Issued at 1119 AM CDT Sun Aug 17 2014 Good new is the upper level system that has plagued the area is forecast to pick up speed and is forecast to be over eastern Ohio by 18z Monday. The bad news is ample low level moisture remains to keep MVFR/IFR ceilings and visibilities in place overnight into Monday. Area of light rain moving over east central MO and southwest IL may be the end of the precipitation as it has a back edge. HRRR model wants to produce scattered showers this afternoon but the other short range models trend to dry so will go with the concensus. Any improvement in cloud conditions this evening will lead to quick fog development, so in essence: pick your poison. Expect most terminals to be MVFR to VFR at the end of the forecast period. Specifics for KSTL: Not much improvement expected overall until 18z Monday. Extensive area of MVRR/IFR ceilings and fog expected to remain in place overnight with the surface to boundary layer relative humidity staying very high. Some light rain moving through now looks like it will end in an hour or so via radar trends. If system moves as it is forecast the goal will be to see VFR by 18z Monday. JPK && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1138 AM CDT Sun Aug 17 2014 .SHORT TERM: (Today) Issued at 343 AM CDT Sun Aug 17 2014 Vorticity maxima/MCV will slowly move to the southeast to around KSLO by mid morning. Precipitation shield overnight as largely been tied to forcing via aforementioned vort max as well as WSW LLJ. Convection on nose of LLJ has already moved off to the south and east of forecast area so primary focus will be on track of closed low/MCV. Since it will be exiting the CWA around late morning...believe highest PoPs this morning will be across portions of southwest Illinois or far eastern sections of the CWFA. With subsidence setting in behind this feature...believe measurable showers/storms will be tough to come by. Weak convergence along trailing sfc inverted trough may yield areas of drizzle beneath low ceilings however. Similar to previous forecaster...leaned cool for high temperatures today yielding upper 70s to low 80s or 5-10 degrees below average. This is due to weak cold advection and low clouds hanging around through the daylight hours. Gosselin .LONG TERM: (Tonight through Saturday) Issued at 343 AM CDT Sun Aug 17 2014 (Tonight - Wednesday night) Slowly decreasing clouds should be the rule tonight with mild temperatures. Lows should be near or slightly above average in the mid 60s to low 70s. A potential issue tonight could be fog...as boundary layer will remain very moist. Due to uncertainty in cloud cover overnight tonight...elected not add fog to forecast for now. Monday should also be dry with warmer conditions returning. By Monday night...a shortwave trough transverses northern sections of the area with a trailing cold front swinging in from the northwest. Raised PoPs into the high chance category over portions of central and northeastern Missouri where combination of strongest moist/warm advection and upper-air dynamics interact. Weak Pacific "cold" front will wash out and stall across southern sections of the area on Tuesday as upper-level heights begin to climb. Raised highs across portions of the region on Tuesday due to favorable WSW downslope sfc flow and partly cloudy skies expected. Chances of showers and thunderstorms will continue and move northward through the region Tuesday night through Wednesday night invof retreating warm frontal boundary as upper-level heights climb. (Thursday - Saturday) Warm front is expected to move northward of the CWA by Thursday as upper ridge continues to build into mid-Mississippi Valley. Some concern that antecedent convection may prevent or retard northward progression of warm front or effective baroclinic zone. Also some uncertainty as to how far north upper ridge will build in...as models tonight have backed off the strength of 500-hPa anticyclone. This could result in increased cloudiness/PoPs and consequently lower temperatures for Thursday and maybe Friday as parts of the forecast area... especially far northern sections...may be on northern edge of upper ridge or in the so-called "ring of fire". Current forecast package still reflects the scenario where upper ridge does indeed build in late in the work week brining potentially our hottest stretch of weather all summer...but again due to the possibilities above...that is not a given at this juncture. Gosselin && .AVIATION: (For the 18z TAFs through 18z Monday Afternoon) Issued at 1119 AM CDT Sun Aug 17 2014 Good new is the upper level system that has plagued the area is forecast to pick up speed and is forecast to be over eastern Ohio by 18z Monday. The bad news is ample low level moisture remains to keep MVFR/IFR ceilings and visibilities in place overnight into Monday. Area of light rain moving over east central MO and southwest IL may be the end of the precipitation as it has a back edge. HRRR model wants to produce scattered showers this afternoon but the other short range models trend to dry so will go with the concensus. Any improvement in cloud conditions this evening will lead to quick fog development, so in essence: pick your poison. Expect most terminals to be MVFR to VFR at the end of the forecast period. Specifics for KSTL: Not much improvement expected overall until 18z Monday. Extensive area of MVRR/IFR ceilings and fog expected to remain in place overnight with the surface to boundary layer relative humidity staying very high. Some light rain moving through now looks like it will end in an hour or so via radar trends. If system moves as it is forecast the goal will be to see VFR by 18z Monday. JPK && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1136 PM CDT Sat Aug 16 2014 .UPDATE: Issued at 942 PM CDT Sat Aug 16 2014 The latest water vapor and VWP data suggest the mid level low/vort max is located near KUIN. The associated surface low is just east of Mexico with a warm front trailing southeast through the St. Louis metro area and cold front extending to just east of the Lake of the Ozarks. The air mass along and ahead of these features is very moist with PWs average around 1.80 inches and warm cloud depths are running 3.5-4.0 km. While this speaks to the efficiency of rainfall production, thus far there has been a lack of overall mesoscale organization and convection has been moving, resulting in spotty rainfall totals of just over 2 inches since this afternoon. Short term guidance from the RAP and HRRR move the vort max to just southeast of St. Louis by 12z with a nearly vertically stacked surface low. The southwesterly LLJ is forecast to increase some to around 30 kts ahead of the system while the current CAPE stream of 1000-1500 J/KG will gradually wane. Present indications given these trends suggest 2 zones with the highest probability of locally heavy rain - 1) south of St. Louis across the eastern Ozarks into southern Illinois more coincident with the LLJ axis and 2) north of St. Louis from roughly Pike County IL to Fayette County IL more associated with mesoscale forcing with the MCV. The current mention of locally heavy rain has this covered well and if a greater threat materializes will update accordingly. Glass && .SHORT TERM: (Through Late Tonight) Issued at 347 PM CDT Sat Aug 16 2014 We have entered a quiet period of weather early this afternoon as the atmosphere re-organizes itself. Just entering extreme northeast MO was a powerful 50-something MCV, and with the very moist atmospheric column in place where PWs were in excess of two inches, it is having no problem in perpetually generating rain around it. Extending to the southwest of this important upper level feature was a surface cold front: from just W of Moberly to just N of Sedalia. This front was intersecting a very moist atmosphere as well, where surface dewpoints were in the low 70s and PWs near two inches, and an unstable atmosphere as well, with MLCAPES up to 3000 J/kg. This front was just beginning to ignite some TSRA along it. Further downstream into eastern MO and southern IL, temps were just beginning to recover into the upper 70s and low 80s where clouds and rain had previously dominated. The atmosphere is essentially primed and merely needs a trigger to get the next round of rain going. Moisture convergence should be at sufficient levels for TSRA to get going along the front, but have also noted that convergence was also beginning to increase over STL metro and southeast MO where a window of opportunity for additional development will present itself between now and early this evening. Otherwise, primary foci will be surface front and MCV as they both very slowly progress southeastward thru our region tonight and continue on Sunday morning...finally expected to leave and pull away Sunday afternoon. As stated earlier, PWs will be in excess of two inches, which is greater than two standard deviations from the mean for mid-August, and models are also forecasting rather deep warm cloud layers over 4km. Greatest threat for excessive rainfall will be an area sandwiched between the MCV, the broadscale lift from the mid level shortwave, and the trailing surface front. This all seems to point to an area from east-central MO and throughout southwest IL, including STL metro. The problem is that 6hr FFG values are mainly above 3 inches, with a small area just north of STL metro where it is as low as 2.5 inches. Given this, will pass these concerns on to evening shift and let them see how convection develops before issuance of any Flood Watch. Categorical PoPs were forecasted thru this system`s conclusion on Sunday with a warm and muggy night ahead tonight and a cool day on Sunday with substantial lo clouds in the system`s wake expected. TES .LONG TERM: (Sunday through Next Saturday) Issued at 347 PM CDT Sat Aug 16 2014 A somewhat drier atmosphere is in place for Monday and with a lack of upper level support and a decent lo level cap in place, should see one day of dry wx. A weak cold front drops down on late Monday night and lingers thru late Wednesday and will result in a threat for thunderstorms. Depending on where the front settles, it will separate seasonable warmth to the north from summertime heat in the south. This summertime heat will be coupled with humidity that may result in 100 heat index values for parts of the area Tuesday and Wednesday afternoons. By late next week, there trend will be for drier and hotter wx as an upper ridge builds overhead and may result in the summer we nearly missed. Looks like a period of a few more days of max temps in the 90s with heat index values between 100-105. May need a heat headline at some point for quite a few areas for next week as a result. TES && .AVIATION: (For the 06z TAFs through 06z Sunday Night) Issued at 1114 PM CDT Sat Aug 16 2014 A slow-moving low pressure system will continue to bring scattered SH/TS to the terminals over the next few hours. Coverage will probably be greater at St. Louis metro area TAF sites due to their proximity to the low. Once the precipitation moves out, ceilings should drop to IFR and remain there for the rest of the night and into tomorrow. There will probably also be transient MVFR to IFR visibilities in fog overnight because of the highly saturated air mass, but models are forecasting winds to stay high enough overnight that it looks more like a low stratus situation rather than widespread dense fog. Ceilings should slowly improve during the afternoon as the low pressure system moves away from the area. Prevailing winds will eventually turn around to the north behind a cold front and on the back side of the departing surface low. Kanofsky && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
657 PM CDT MON AUG 18 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON AUG 18 2014 THE MAIN FORECAST ISSUE WILL BE THE POSSIBILITY OF SOME THUNDERSTORM ACTIVITY IN THE FAR SOUTHERN CWA OVERNIGHT. WEST NORTHWEST FLOW ALOFT IS FAIRLY WEAK AND A NEARLY STALLED BOUNDARY ACROSS THE CWA CONTINUES TO DRIFT SOUTH TODAY. LITTLE IF ANY DEVELOPMENT SHOULD DEVELOP ALONG THIS BOUNDARY TODAY INTO THIS EVENING AS A FAIRLY HEALTHY CAP KEEPS THINGS QUIET...DESPITE MODERATE INSTABILITY IN THE 1500 TO 2000 J/KG RANGE FOR CONVECTIVE AVAILABLE POTENTIAL ENERGY. SOME SMALL POP-UPS ARE SHOWING UP JUST NORTH OF THE CWA...BUT THERE SHOULD BE ENOUGH OF A CAP TO TAMP MUCH FURTHER DEVELOPMENT IN THE NORTH. LATER ON TONIGHT...A HEALTHY 40 TO 45 KT JET WILL DEVELOP OVER KANSAS AND WILL CURVE EAST...MOSTLY LIKELY OVER NORTH CENTRAL KANSAS. THIS WILL SET THE STAGE FOR SOME POTENTIAL LOW-LEVEL CONVERGENCE ACROSS OUR SOUTHERN CWA IN NORTH CENTRAL KANSAS AND FAR SOUTHERN NEBRASKA NEAR THE AFOREMENTIONED SURFACE BOUNDARY. THIS COULD BE JUST ENOUGH SUPPORT FOR SOME SMALL HAIL AND GUSTY WIND IN OUR FAR SOUTH AS WELL. THE HRRR IS TRENDING STRONGER WITH SOME DEVELOPMENT OVER THE HIGH PLAINS THIS AFTERNOON...SUPPORTED BY ANOTHER LOW-AMPLITUDE SHORTWAVE TROUGH. THIS COULD BE ENHANCED BY THE DEVELOPING LOW-LEVEL JET IN KANSAS AS THIS POTENTIAL CONVECTION HEADS SOUTH. THE NAM HAS BEEN ADVERTISING SOME ACTIVITY IN THIS VICINITY FOR THE PAST COUPLE OF DAYS. THE PRUDENT ACTION WOULD BE TO PUT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST IN OUR SOUTH. OUR CHANCES OF RAIN ARE LARGELY DEPENDENT ON INITIAL CONVECTION IN THE HIGH PLAINS WITHIN THE STRONGLY UNSTABLE...YET STILL CAPPED ENVIRONMENT TO THE WEST AS THE AFOREMENTIONED TROUGH ENTERS THE CENTRAL PLAINS. THE SREF SOLUTIONS ARE ALSO COMING IN WITH STRONGER SIGNALS TOWARD CONVECTION IN OUR SOUTH AS WELL. FOR TUESDAY...KEEPING IT QUIET WITH THE THINKING THAT THERE SHOULD BE ENOUGH OF A CAP FROM PRECLUDING DEVELOPMENT UNTIL THE EVENING HOURS. HIGH PLAINS CONVECTION COULD DEVELOP DURING THE DAY...BUT SHOULD HOLD OFF MAKING IT HERE UNTIL EVENING...WHEN A LOW-LEVEL JET AXIS DEVELOPS JUST TO THE WEST OF THE CWA. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON AUG 18 2014 GUIDANCE SUGGESTS UPPER TROPOSPHERIC RIDGING WILL EXIST OVER THE CENTRAL CONUS TO START THE LONG TERM FORECAST PERIOD. THE RIDGE AXIS IS EXPECTED TO SHIFT EAST SOMEWHAT BY THURSDAY OR FRIDAY HOWEVER...ALLOWING FOR MORE OF A SOUTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA LATE THIS WEEK INTO EARLY NEXT WEEK. THE AXIS OF A 35-40KT LOWER TROPOSPHERIC JET STREAK...JUST ABOVE THE BOUNDARY LAYER...IS EXPECTED DEVELOP FROM WESTERN KANSAS INTO SOUTH CENTRAL NEBRASKA TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. THERMAL ADVECTION ALONG THIS AXIS APPEARS AS THOUGH IT WILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS NORTHEASTERN PORTIONS OF OUR CWA...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. WENT AHEAD WITH 20-30% POPS ACROSS OUR NORTHEAST TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AS A RESULT. ON OVERALL LACK IN OMEGA SHOULD THEN PROVIDE DRY CONDITIONS TO OUR AREA THROUGH MUCH OF THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON HOWEVER...THE NAM AND OPERATIONAL GFS BOTH SUGGEST CONVECTION WILL INITIATE OVER THE CENTRAL HIGH PLAINS...AND THEN MOVE EAST INTO OUR AREA WEDNESDAY EVENING AND OVERNIGHT. GIVEN THIS...WENT AHEAD WITH 20-30% POPS ACROSS MUCH OF THE CWA WEDNESDAY EVENING AND NIGHT. ALTHOUGH OMEGA IS EXPECTED TO REMAIN WEAK THROUGH THE DAY THURSDAY AS WELL...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST A NEARLY DRY ADIABATIC TEMPERATURE PROFILE WILL BE REALIZED FROM THE SURFACE TO JUST ABOVE 700MB ACROSS MUCH OF THE CWA...THUS ALLOWING CONVECTIVE TEMPERATURE READINGS TO BE REACH AND PROVIDING FOR ISOLATED THUNDERSTORM DEVELOPMENT. THIS IS A SOLUTION ALSO SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. GIVEN ALL THIS...WENT AHEAD WITH ~20% POPS ACROSS MUCH OF THE CWA THURSDAY AFTERNOON AND EVENING. HEADING INTO THURSDAY NIGHT AND BEYOND...GUIDANCE SUGGESTS MULTIPLE UPPER TROPOSPHERIC PERTURBATIONS COULD MOVE OVER THE CENTRAL PLAINS AS THE SOUTHWESTERLY UPPER TROPOSPHERIC FLOW INTENSIFIES. ALLBLEND RESPONDED BY PROVIDING 20-50% POPS TO MANY AREAS ACROSS THE CWA THURSDAY NIGHT THROUGH MONDAY...AND THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART. FORECAST PROXIMITY SOUNDINGS FROM THE NORTHEASTERN CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST STORM-ACCESSIBLE POTENTIAL ENERGY WILL NOT EXCEED 200-300J/KG TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AND THUS...WILL HOLD OFF FROM ANY MENTION OF SEVERE WEATHER TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. CONVECTION ALONG THE CENTRAL HIGH PLAINS WEDNESDAY AFTERNOON AND EVENING WILL LIKELY HAVE THE CAPABILITY TO BE STRONG...BUT THERE IS CONSIDERABLE UNCERTAINTY AS TO HOW LONG THIS CONVECTION WILL BE ABLE TO MAINTAIN ITS INTENSITY AS IT MOVES EAST INTO OUR AREA. GIVEN THIS UNCERTAINTY...WILL HOLD OFF FROM ANY MENTION OF SEVERE WEATHER ACROSS OUR AREA WEDNESDAY EVENING AND LET FUTURE SHIFTS REEVALUATE. BEYOND WEDNESDAY EVENING...AT THIS TIME THERE ARE NO OVERWHELMING SIGNALS OF A SIGNIFICANT SEVERE WEATHER OUTBREAK. ALTHOUGH A FEW HIT AND MISS STRONG TO SEVERE STORMS PROBABLY CANNOT BE RULED OUT...DUE TO THE UNCERTAINTY WILL LEAVE OUT ANY MENTION OF SEVERE WEATHER WEDNESDAY NIGHT AND BEYOND. LITTLE CHANGE IN THE LOWER TROPOSPHERIC AIR MASS SHOULD PROMOTE SIMILAR TEMPERATURE READINGS FROM DAY TO DAY WEDNESDAY THROUGH SATURDAY...WITH AFTERNOON HIGHS IN THE UPPER 80S AND 90S AND OVERNIGHT LOWS IN THE 60S AND LOWER 70S EXPECTED FOR THE MOST PART. BEYOND SATURDAY...GUIDANCE DOES SUGGEST A LOWER TROPOSPHERIC BAROCLINIC ZONE WILL MOVE ACROSS THE AREA...THUS ALLOWING A COOLER LOWER TROPOSPHERIC AIR MASS INTO THE REGION. AFTERNOON HIGHS IN THE UPPER 70S TO MID 80S AND LOWS GENERALLY IN THE 60S ARE CURRENTLY EXPECTED TO FINISH THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 652 PM CDT MON AUG 18 2014 VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE TAF VALID PERIOD. THUNDERSTORMS TO THE WEST THIS EVENING ARE EXPECTED TO REMAIN WEST OF BOTH KEAR AND KGRI. THE WIND WILL BE LIGHT AND VARIABLE THROUGH TUESDAY MORNING...POSSIBLY BECOMING MORE PREDOMINATELY OUT OF THE SOUTHEAST BY TOMORROW AFTERNOON...BUT WILL REMAIN LIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...BRYANT AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
313 PM CDT SUN AUG 17 2014 .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 305 PM CDT SUN AUG 17 2014 ...OUR PATTERN REMAINS UNSETTLED...AND WARMER THIS WEEK... FORECAST CHALLENGES FOR THE SHORT TERM WILL BE THUNDERSTORM CHANCES AND SEVERE POTENTIAL TONIGHT THROUGH MONDAY EARLY AFTERNOON. IT LOOKED FAIRLY QUIET WEATHER TO BEGIN THIS EVENING...HOWEVER IT SEEMS LIKE THE SHORT RANGE MODELS ARE A BIT UNDERDONE WITH THE CONVECTION OVER CENTRAL SOUTH DAKOTA BASES ON THE LATEST RADAR. THE HRRR HAS A SHORTWAVE AND CONVECTION THAT DROPS SOUTHEAST ACROSS THE FORECAST AREA. THIS EVENING...WHILE THE OTHER MODELS ARE SLOWER AND LESS AGGRESSIVE UNTIL LATER TONIGHT. EVEN THE 18Z NAM IS STILL DRY THIS EVENING. NOT SURE HOW HIGH TO GO EARLY...BUT WILL INCLUDE ISOLATED THUNDERSTORMS FOR PARTS OF NORTHEAST NEBRASKA EARLY THIS EVENING. THE STORM PREDICTION CENTER DOES HAVE A SEVERE THUNDERSTORM WATCH OUT FOR COUNTIES JUST TO THE WEST OF OUR FORECAST AREA THIS EVENING AND THE SLIGHT RISK FOR SEVERE WEATHER DOES CLIP OUR WESTERN FORECAST AREA COUNTIES. THE 12Z UPPER AIR MAPS SHOWED A RIDGE OVER THE SOUTHWEST U.S. WITH A CLOSED LOW OVER SASKATCHEWAN AND LEADING SHORTWAVE TROF ENERGY OVER MINNESOTA. THE STRONGER HEIGHT FALLS AT H5 WERE NOTED OVER CANADA...ASSOCIATED WITH THIS NORTHERN SYSTEM. THERE WERE RIBBONS OF POOLED H7 MOISTURE OVER THE PLAINS WITH THE H7 THERMAL RIDGE OVER WESTERN NEBRASKA AND COLORADO. SIMILAR PATTERNS WERE NOTED AT H85. THE OAX SOUNDING HAD A PWAT OF 1.44 INCHES WHICH WAS 134% OF NORMAL. A MAX OF 185% OF NORMAL WAS CENTERED OVER KMPX. AS THE EVENING PROGRESSES...A LOW LEVEL JET INCREASES TO 35-40KTS OVER CENTRAL NEBRASKA...MEANWHILE THE SHORTWAVE TROF ENERGY OVER CANADA EXTENDS SOUTHWARD INTO THE PLAINS. UPPER LEVEL JET SUPPORT...OMEGA... FRONTOGENESIS AND THETA-E ADVECTION ALL INCREASE. AS A RESULT...THE DETERMINISTIC MODELS INCREASE CONVECTION OVER THE DAKOTAS AND THIS CONVECTION EXTENDS SOUTHWARD INTO EASTERN NEBRASKA AND IOWA TONIGHT AND MONDAY. THERE IS A GOOD H7 WARM AIR ADVECTION SIGNAL AND GOOD 7-8 DEG C H7 DEWPOINTS. EXPECTED TRENDS LATER TONIGHT ARE WELL HANDLED BY THE CURRENT FORECAST WITH INCREASING POPS INTO THE LIKELY CATEGORY AND WILL TREND FARTHER SOUTH TO COVER POTENTIAL FOR INCREASED CONVERGENCE CLOSER TO THE SURFACE LOW. DEEP LAYER SHEAR IS FROM 30- 40KTS TONIGHT...HOWEVER DROPS CLOSER TO 30KTS MONDAY. THE SURFACE AND H85 FRONT ARE STILL IN EASTERN NEBRASKA MONDAY MORNING...AND GRADUALLY PUSH OUT OF THE FORECAST AREA BY 00Z MONDAY. INSTABILITY IS 500-2000J/KG TONIGHT...BUT INCREASES TO 3000+ MONDAY. FORECAST SOUNDINGS LOOK TO FAVOR ELEVATED STORMS TONIGHT...HOWEVER THEY ARE MORE SURFACE BASED FOR MONDAY. ALTHOUGH FREEZING LEVELS ARE HIGHER AND INSTABILITY IS O.K. STRONGER SHEAR...PLUME OF STEEPER LAPSE RATES AND BETTER LOW AND MID LEVEL FORCING MAY SUPPORT SOME SEVERE STORMS. SEVERE WEATHER CHANCES CONTINUE INTO MONDAY AS THUNDERSTORMS WILL BE ONGOING WITH INCREASED INSTABILITY...ALTHOUGH FORCING AND SHEAR APPEAR TO BE NOT AS HIGH. TREND WITH HIGHER POPS IN THE AM...DECREASING FROM WEST TO EAST IN THE AFTERNOON. STORM MOTION IS AROUND 20KTS...BUT WITH HIGH PWATS/H7 DEWPOINTS AND POTENTIAL FOR STORMS MOVING OVER THE SAME AREA COULD PRODUCE HEAVY RAIN. MAINLY DRY FOR MONDAY NIGHT INTO TUESDAY WITH A WARM FRONT SITUATED OVER NORTHERN KANSAS. THERE IS LIFT OVER THE FRONT AND THE FRONT LIFTS NORTH TUESDAY NIGHT AND WEDNESDAY...SO HAVE SCATTERED THUNDERSTORMS MENTIONED. WARMER HIGHS IN THE 90S CAN BE EXPECTED SOUTH OF THE FRONT. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 305 PM CDT SUN AUG 17 2014 STILL QUITE A FEW MODEL DIFFERENCES WEDNESDAY NIGHT THROUGH SUNDAY. IT LOOKS LIKE A FRONT WILL BE IN THE AREA WEDNESDAY NIGHT THROUGH FRIDAY...WITH A MID LEVEL RIDGE TO OUR SOUTH AND A FLATTER...TROF INFLUENCE TO OUR NORTH. WARM H85 TEMPS FROM 20-24 DEG C PERSIST THROUGH FRIDAY NIGHT...HOWEVER THE EC BRINGS COOLER WEATHER IN FOR SATURDAY...WHILE THE GFS HOLDS OFF UNTIL SUNDAY NIGHT. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 219 PM CDT SUN AUG 17 2014 HAVE ADJUSTED TIMING OF THUNDERSTORMS AT TAF LOCATIONS BASED ON MOST RECENT HI RESOLUTION HRRR AND NAM ARW MODEL DATA. STORM DEVELOPMENT ACROSS NORTH CENTRAL NEBRASKA COULD REACH THE KOFK BY 03Z WHERE WE WENT WITH A TEMPORARY GROUP WITH VARIABLE WINDS 15 TO 25 KNOTS. STILL KEPT A PROB30 GROUP FOR KLNK BY 04Z AND KOMA BY 06Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...ZAPOTOCNY LONG TERM...ZAPOTOCNY AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
219 PM CDT SUN AUG 17 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 340 AM CDT SUN AUG 17 2014 SIMILAR TO LAST NIGHT...THE PRIMARY NEAR-TERM CONCERN IS DENSE FOG...THIS TIME OVER SOUTHWEST IOWA. METARS FOR SDA/ICL/RDK/AIO HAVE BEEN BOUNCING AROUND 1/4 TO 1/2 MILE VISIBILITIES. MUCH OF THIS DENSE FOG IS TIED TO LAST NIGHTS RAINFALL AND GIVEN THE LIGHT WIND REGIME IN PLACE SHOULD HAVE NO TROUBLE STICKING AROUND UNTIL AFTER DAYBREAK. FOR TODAY EXPECT DRY WEATHER...AT LEAST UNTIL EARLY EVENING...AS THE AREA IS IN BETWEEN SHORTWAVES. BY TONIGHT THE NEXT FEATURE ENTERS FROM THE NORTHWEST ACCOMPANIED BY MODEST HEIGHT FALLS AVERAGING AROUND 4-6 DM. THERE IS A SLIGHT RISK FOR SEVERE WEATHER ACROSS NORTH CENTRAL NEBRASKA...FOR OUR AREA CONDITIONS JUST AREN/T IN PLACE FOR MUCH OF A SEVERE WEATHER CONCERN. INTO THE OVERNIGHT HOURS...INSTABILITY WANES AND DEEP LAYER SHEAR VALUES ARE MARGINAL ALONG WITH A LOW-LEVEL JET DISPLACED WELL TO OUR WEST. AN ISOLATED SEVERE THUNDERSTORM ACROSS OUR FAR WESTERN COUNTY WARNING AREA CANNOT BE RULED OUT AS STRONG STORMS PROPAGATE EAST...BUT THE PRIMARY THREAT FOR US WILL BE HEAVY RAIN. MONDAY AND TUESDAY...ANY LEFTOVER SHOWERS AND THUNDERSTORMS WILL BE MOVING EAST BY LATE MONDAY MORNING...LEAVING A DRY FORECAST FOR MUCH OF MONDAY AFTN/EVENING AND THROUGH TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 340 AM CDT SUN AUG 17 2014 BY TUESDAY NIGHT THE NEXT SHORTWAVE WILL MOVE INTO CENTRAL AND EASTERN NEBRASKA. ITS HARD TO SAY THIS WILL BE A GOOD CHANCE AT MEASURABLE RAIN GIVEN HOW HIT AND MISS PRECIPITATION HAS BEEN RECENTLY. FOR NOW WILL GO WITH A HIGH CHANCE FOR SHOWERS AND THUNDERSTORMS AND EXPECT TIMING/PLACEMENT TO WORK ITSELF OUT IN FORTHCOMING MODEL RUNS. THEREAFTER THE FORECAST PICTURE IS QUITE UNCLEAR WITH A SIMILAR STORY OF SHORTWAVES MOVING THROUGH THE REGION. LATEST LONG TERM GUIDANCE HINTS AT A STRONG COLD FRONT MOVING THROUGH LATE NEXT WEEKEND...BRINGING A DOSE OF COOLER AIR AND VERY UNSETTLED WEATHER. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 219 PM CDT SUN AUG 17 2014 HAVE ADJUSTED TIMING OF THUNDERSTORMS AT TAF LOCATIONS BASED ON MOST RECENT HI RESOLUTION HRRR AND NAM ARW MODEL DATA. STORM DEVELOPMENT ACROSS NORTH CENTRAL NEBRASKA COULD REACH THE KOFK BY 03Z WHERE WE WENT WITH A TEMPORARY GROUP WITH VARIABLE WINDS 15 TO 25 KNOTS. STILL KEPT A PROB30 GROUP FOR KLNK BY 04Z AND KOMA BY 06Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...PEARSON LONG TERM...PEARSON AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT SAT AUG 16 2014 .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 248 PM CDT SAT AUG 16 2014 THE AREA REMAINS IN BETWEEN TWO UPPER SYSTEMS WITH ONE WELL TO OUR NORTH AND ANOTHER TO OUR EAST. CONVECTION COULD STILL DEVELOP IN NORTHEAST NEBRASKA ON THE FAR SOUTHERN EXTENT OF THE NORTHERN SYSTEM...WITHIN A SLIGHTLY AGITATED CU FIELD BETWEEN KBVN...KONL AND KYKN...AS SUGGESTED BY THE HRRR MODEL. ANY ANYTHING INDEED DEVELOPS EARLY THIS EVENING...IT WOULD PROBABLY DIMINISH/END BY MIDNIGHT...ALTHOUGH THE NAM WOULD HOLD IT TOGETHER ACROSS EASTERN NEBRASKA THROUGH THE WEE HOURS. FOCUS THEN SHIFTS TO FOG REDEVELOPMENT OVERNIGHT AS AMPLE LOW LEVEL MOISTURE REMAINS WITH SURFACE DEWPOINTS IN THE UPPER 60S TO LOWER 70S. WINDS WILL LIKELY GO CALM IN MANY PLACES OVERNIGHT. MET/MAV/LAV GUIDANCE ALL INDICATES FOG WILL REDEVELOP BY 06Z...AND COULD BECOME LOCALLY DENSE BY 09-11Z...THEN LIFTING/BURNING OFF BY 14-15Z. HAVE ADDED PATCHY DENSE FOG INTO THE GRIDS...AND MAY HAVE TO EVENTUALLY ISSUE A DENSE FOG ADVISORY FOR PARTS OF THE REGION TONIGHT AS CONDITIONS MATERIALIZE. AREAS MOST SUSCEPTIBLE INCLUDE ALL OF WESTERN IOWA...THE THE PLATTE AND MISSOURI RIVER VALLEYS. CONVECTIVE DEVELOPMENT SUNDAY IS ALSO QUESTIONABLE...BUT THE LINGERING VERY SUBTLE TROUGH WITH ASSOCIATED ACTIVITY THIS EVENING COULD BE ALONG THE MISSOURI RIVER SUNDAY AFTERNOON...THUS WILL MAINTAIN JUST 20 PERCENT CHANCE OF STORMS ALONG/EAST OF THE MISSOURI RIVER THROUGH PEAK HEATING TOMORROW. SHOULD BE ANOTHER DRY PERIOD SUNDAY EVENING...BUT CONVECTION CHANCES INCREASE AGAIN BY DAYBREAK MONDAY AS THE NEXT IMPULSE BEGINS TO MOVE INTO THE AREA FROM THE HIGH PLAINS. RAIN CHANCES CONTINUE MONDAY...AND MAY LINGER FOR SOUTHEAST NEBRASKA MONDAY NIGHT...BUT SHOULD BE DRY AGAIN FOR TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 248 PM CDT SAT AUG 16 2014 ANOTHER SLOW MOVING WAVE MOVES INTO THE REGION TUESDAY NIGHT THROUGH WEDNESDAY NIGHT BRINGING ONE MORE CHANCE OF STORMS TO THE AREA. RIDGING THEN BUILDS BACK ACROSS THE PLAINS FOR THE END OF THE WEEK WITH DRY WEATHER...AND TEMPS WARMING INTO THE LOWER 90S AGAIN. COULD SEE A NOCTURNAL CHANCE OF STORMS UNDERNEATH THE RIDGE FRIDAY NIGHT. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1145 PM CDT SAT AUG 16 2014 WE ARE STILL LOOKING FOR DETERIORATING CONDITIONS OVERNIGHT WITH FOG DEVELOPING. ISOLD TSRA CONTINUE TO DRIFT EASTWARD TO THE EAST AND NORTHEAST OF KOFK. THERE ARE HINTS THAT SOME OF THIS ACTIVITY COULD AFFECT KOMA LATE TONIGHT...BUT CHANCES SEEMED LOW ENOUGH TO LEAVE IT OUT OF THE TAF FOR NOW. LIGHT SOUTHEAST WINDS OVERNIGHT AND PLENTY OF LOW LEVEL MOISTURE IN PLACE STILL SUGGEST FOG WILL DEVELOP. THERE WAS ALREADY SOME FOG IN SOUTHWEST IOWA. THE FOG AND LOW CLOUDS SHOULD GRADUALLY LIFT/BREAK UP BY MID TO LATE MORNING WITH VFR CONDITIONS FOR THE AFTERNOON. THE CHANCE FOR TSRA SHOULD INCREASE SUNDAY NIGHT...MAINLY AFTER ABOUT 06Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
320 PM EDT SUN AUG 17 2014 .SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES IN WEST-NORTHWESTERLY FLOW WILL CROSS THE REGION THIS WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM SUNDAY... DIURNAL DESTABILIZATION WILL YIELD MODERATE INSTABILITY IN MOST AREAS THIS AFTERNOON. HOWEVER...FORCING FOR ASCENT WILL BE LIMITED (AT BEST) TO TRANSIENT SMALL AMPLITUDE DISTURBANCES IN WNW FLOW ALOFT...FEATURES WHICH ARE EITHER ABSENT OR DIFFICULT TO RESOLVE PER LATEST WV IMAGERY AND RAP DATA. WILL CONTINUE TO INDICATE A DRY FORECAST...WITH HIGH IN THE UPPER 80S TO LOWER/MID 90S. A MORE DETAILED DISCUSSION WILL BE FORTHCOMING. -VINCENT && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 AM SUNDAY... THE MCV CURRENTLY IN THE VICINITY OF KSTL...WHICH IS RATHER STRONG BASED ON SATELLITE PRESENTATION...IS FORECAST TO CROSS THE APPALACHIANS BY MIDDAY MONDAY....WITH A SHARPENING PIEDMONT TROUGH. GFS FORECAST SOUNDINGS GIVE 1000-2000 J/KG OF MLCAPE... HIGHER IN THE EAST WHERE HEATING WILL BE FAVORED AND LAPSE RATES STEEPEN THE MOST. PW INCREASES TO OVER 2 INCHES BY MONDAY AFTERNOON...AND COMBINED WITH THE FORCING AND INSTABILITY SHOULD SUPPORT SCATTERED STORMS. THE LARGER SCALE SHEAR IS EXPECTED TO BE RELATIVELY WEAK...20-25KT...THOUGH THE DISTURBANCE MAY AUGMENT SHEAR LOCALLY AS IT CROSSES THE AREA. HOWEVER...HIGH PW AND STEEP LOW-LEVEL LAPSE RATES MAY STILL CREATE THE POTENTIAL FOR A FEW STRONG WIND GUSTS. HIGHS 88-93. SHOULD SEE SOME CLEARING BEHIND THE UPPER DISTURBANCE ON MONDAY NIGHT AND THE POTENTIAL FOR SOME PATCHY FOG DEPENDING ON WHERE STORMS OCCUR. LOWS UPPER 60S TO LOWER 70S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 320 PM SUNDAY... THE UPPER AIR PATTERN AT THE BEGINNING OF THE LONG TERM PERIOD INCLUDES A GENERAL WESTERLY FLOW WITH A WEAK SHEAR AXIS EXTENDING FROM NORTH TO SOUTH ACROSS THE MID ATLANTIC. DURING THE REMAINDER OF THE LONG TERM PERIOD THE PATTERN EVOLVES AS BOTH THE GFS AND THE ECMWF DEVELOP A LARGE RIDGE ACROSS THE LOWER MISSISSIPPI VALLY ON THURSDAY WITH 5950M HEIGHTS THAT PERSISTS INTO EARLY SATURDAY. GUIDANCE DIVERGES A BIT AT THAT TIME AS THE RIDGE IN THE ECMWF WEAKENS AND A BROAD TROUGH SWEEPS ACROSS THE NORTHERN ROCKIES AND NORTHERN PLAINS ON SUNDAY WHILE THE GFS HOLDS ONTO A STRONGER RIDGE. REGARDLESS... CENTRAL NC WILL BE IN A NORTHWEST FLOW ALOFT FOR MUCH OF THE PERIOD WITH A THREAT OF SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS EACH DAY. NEAR TO ABOVE AVERAGE HIGH TEMPERATURES WILL COOL DOWN TO NEAR TO BELOW AVERAGE AS A COLD FRONT PUSHES SOUTH THROUGH THE REGION. ONE SHORTWAVE TROUGH AND AN ASSOCIATED SURFACE LOW WILL MOVE OFFSHORE TUESDAY MORNING BEFORE ANOTHER DISTURBANCE ALOFT MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. CONVECTIVE COVERAGE SHOULD BE MUCH LESS ON TUESDAY THAN ON MONDAY WITH THE GREATEST COVERAGE IN THE EAST AHEAD OF THE BEST FORCING AND IN THE REGION OF DEEPEST MOISTURE. NOT TOO EXCITED ABOUT SIGNIFICANT SEVERE WEATHER WITH THE SREF SUGGESTING A WEAK TO MODERATELY UNSTABLE AIR MASS WITH BULK SHEAR VALUES PEAKING AROUND 20-25KTS. BUT THE FLOW HIGHS SHOULD RANGE IN THE UPPER 80S TO LOWER 90S. GUIDANCE DEPICTS A SIMILAR PATTERN ACROSS THE CAROLINAS FOR THE MID TO END OF THE LONG TERM PERIOD AS A NORTHWEST FLOW ALOFT DRIVES MULTIPLE IMPULSES ACROSS THE REGION. DEEP LAYER MOISTURE IS MORE LIMITED ON WEDNESDAY AND THURSDAY BUT INCREASES MARKEDLY ON FRIDAY INTO THE WEEKEND WITH PRECIPITABLE WATER VALUES ON SAT AND SUN RANGING FROM NEAR 2.1 ACROSS THE COASTAL PLAIN TO 1.8 ACROSS THE WESTERN PIEDMONT. A WEAK COLD FRONT IS PROGGED TO MOVE SOUTH ACROSS THE REGION ON FRIDAY AND SATURDAY AND LIKELY LINGER IN A WEST TO EAST ORIENTATION ACROSS GA/SC AND SOUTHERN NC PROVIDING A FOCUS FOR CONVECTION. ITS DIFFICULT TO PLACE MUCH SPECIFICITY IN THE FORECAST BUT WEDNESDAY AND THURSDAY WOULD APPEAR TO HAVE LESS CONVECTIVE COVERAGE WITH INCREASING CHANCES OF CONVECTION ON FRIDAY INTO THE WEEKEND. HIGH TEMPERATURES IN THE LOWER 90S ON WEDNESDAY AND THURSDAY WILL COOL DOWN A BIT ON FRIDAY AND SHOULD BE NOTICEABLY COOLER FOR SATURDAY AND SUNDAY WITH HIGHS IN THE LOWER TO MID 80S. MORNING LOWS WILL COOL SLIGHTLY FROM THE UPPER 60S TO LOWER 70S AROUND MID WEEK TO THE UPPER 60S TO AROUND 70 BY THE WEEKEND. -BLAES && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 730 AM SUNDAY... WINDS WILL BE LIGHT THROUGH THE PERIOD...GENERALLY OUR OF THE WEST- SOUTHWEST. MID CLOUDS WILL TO STREAM IN FROM THE NORTHWEST...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF NC AS A DISTURBANCE CROSSES THE AREA. IFR/LIFR VSBYS DEVELOP FROM KFAY TO KRWI THIS MORNING BUT ARE ALREADY BEGINNING TO IMPROVE. VFR CONDITIONS SHOULD THUS RETURN BY 14Z AND CONTINUE THROUGH THE REMAINDER OF THE TAF PERIOD. OUTLOOK... BETTER CHANCES FOR SHOWERS AND STORMS LATE MONDAY WITH ANOTHER DISTURBANCE CROSSING THE REGION. THEN THE NEXT PERIOD O UNSETTLED WEATHER LOOKS TO COME LATE IN THE WEEK. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS NEAR TERM...VINCENT SHORT TERM...BLS LONG TERM...BLAES AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1233 PM EDT SUN AUG 17 2014 .SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES IN WEST-NORTHWESTERLY FLOW WILL CROSS THE REGION THIS WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM SUNDAY... DIURNAL DESTABILIZATION WILL YIELD MODERATE INSTABILITY IN MOST AREAS THIS AFTERNOON. HOWEVER...FORCING FOR ASCENT WILL BE LIMITED (AT BEST) TO TRANSIENT SMALL AMPLITUDE DISTURBANCES IN WNW FLOW ALOFT...FEATURES WHICH ARE EITHER ABSENT OR DIFFICULT TO RESOLVE PER LATEST WV IMAGERY AND RAP DATA. WILL CONTINUE TO INDICATE A DRY FORECAST...WITH HIGH IN THE UPPER 80S TO LOWER/MID 90S. A MORE DETAILED DISCUSSION WILL BE FORTHCOMING. -VINCENT && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 AM SUNDAY... THE MCV CURRENTLY IN THE VICINITY OF KSTL...WHICH IS RATHER STRONG BASED ON SATELLITE PRESENTATION...IS FORECAST TO CROSS THE APPALACHIANS BY MIDDAY MONDAY....WITH A SHARPENING PIEDMONT TROUGH. GFS FORECAST SOUNDINGS GIVE 1000-2000 J/KG OF MLCAPE... HIGHER IN THE EAST WHERE HEATING WILL BE FAVORED AND LAPSE RATES STEEPEN THE MOST. PW INCREASES TO OVER 2 INCHES BY MONDAY AFTERNOON...AND COMBINED WITH THE FORCING AND INSTABILITY SHOULD SUPPORT SCATTERED STORMS. THE LARGER SCALE SHEAR IS EXPECTED TO BE RELATIVELY WEAK...20-25KT...THOUGH THE DISTURBANCE MAY AUGMENT SHEAR LOCALLY AS IT CROSSES THE AREA. HOWEVER...HIGH PW AND STEEP LOW-LEVEL LAPSE RATES MAY STILL CREATE THE POTENTIAL FOR A FEW STRONG WIND GUSTS. HIGHS 88-93. SHOULD SEE SOME CLEARING BEHIND THE UPPER DISTURBANCE ON MONDAY NIGHT AND THE POTENTIAL FOR SOME PATCHY FOG DEPENDING ON WHERE STORMS OCCUR. LOWS UPPER 60S TO LOWER 70S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 235 AM SUNDAY... TUESDAY AND TUESDAY NIGHT: TUESDAY WILL SEE A SHORTWAVE AND ASSOCIATED MESO-LOW MOVE THROUGH THE NORTHERN HALF OF THE CWA...ENDING UP NORTHEAST OF THE AREA BY TUESDAY AFTERNOON. THE ASSOCIATED DPVA MAXIMUM IS NOW TRACKING A LITTLE FURTHER SOUTH THAN PREVIOUS RUNS...ENDING UP BETWEEN KFAY AND KRWI BY 18Z TUESDAY. THIS IS CAUSING A VERY SMALL AMPLITUDE SHORTWAVE TROUGH AT 500MB THAT COULD CAUSE CONVECTION TO EXTEND FURTHER SOUTH ALONG THE I-95 CORRIDOR THAN ORIGINALLY THOUGHT ON TUESDAY AFTERNOON/EVENING. WILL RAISE POPS ACCORDINGLY...CLOSER TO 40 PERCENT IN THE EAST...WHILE MAINTAINING SLIGHT CHANCE IN THE WEST. MODEL FORECAST SOUNDINGS DURING THIS TIME INDICATE ABOUT 1000 J/KG OF CAPE AND BULK SHEAR NEAR 20 KTS. VERY STRONG LOW LEVEL LAPSE RATES HELPING TO CREATE INVERTED V SIGNATURES ON THE SOUNDINGS. CANT RULE OUT A SEVERE STORM OR TWO WITH DAMAGING WINDS THE MOST LIKELY SCENARIO BUT SOME SMALL HAIL ALSO POSSIBLE WITH GOOD CAPE IN THE HAIL GROWTH ZONE. WHILE HODOGRAPHS AT KRWI DO SHOW SOME CURVATURE IN THE LOWEST 3 KM...THE SHEAR MAGNITUDE IS VERY LOW AT LESS THAN 10 KTS AND THUS KEEPING HELICITY VALUES DOWN. THIS COUPLED WITH VERY HIGH LCL VALUES MAKES ANY TORNADIC THREAT UNLIKELY. SPC HAS THE AREA IN A GENERIC SEE TEXT FOR THE DAY 3 CONVECTIVE OUTLOOK AT THIS TIME. DUE TO AN INCREASE IN EXPECTED CLOUD COVER/PRECIPIATION COVERAGE...WILL LOWER MAX TEMPS IN THE EASTERN HALF OF THE CWA...UPPER 80S TO NEAR 90 AND MAINTAIN UPPER 80S TO LOW 90S IN THE WEST. EXPECT PRECIPIATION TO WIND DOWN OVERNIGHT TUESDAY AS LOW PULLS OFF TO THE NORTHEAST. LOWS IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH SATURDAY: THE CONFIDENCE IN THE FORECAST BEGINS TO DEGRADE SIGNIFICANTLY AS THE FORECAST PERIOD GOES ON AS MODELS BEGIN TO AMPLIFY A LONGWAVE TROUGH OVER THE EASTERN CONUS WITH STRONG HIGH PRESSURE OVER THE DEEP SOUTH AND INTO THE TEXARKANA REGION AND AN ASSOCIATED RIDGE EXTENDING UP INTO THE CENTRAL PLAINS. WHILE DETERMINISTIC MODELS AMPLIFY THE PATTERN STRONGLY...ENSEMBLE MEANS HAVE BEEN MORE CONSISTENT WITH A MORE MUTED SCENARIO. A SERIES OF SHORTWAVES WILL MARCH THROUGH THE UPPER TROUGH THROUGH SATURDAY MAKING PRECIPITATION POSSIBLE EACH DAY. TOTAL MOISTURE DROPS OFF WEDNESDAY AND THURSDAY MAKING THESE DAYS MORE LIKELY TO REMAIN DRY OR FOR CONVECTION TO BE MORE SCATTERED IN NATURE. A STRONGER SURGE OF MOISTURE RETURNS FOR FRIDAY AND SATURDAY. WILL MAINTAIN SLIGHT CHANCE POPS WEDNESDAY AND THURSDAY AFTERNOONS AND RAMP UP TO CHANCE FOR FRIDAY AND SATURDAY. HIGHS WEDNESDAY AND THURSDAY IN THE LOW 90S AND THEN DROPPING BACK TO THE UPPER 80S FOR FRIDAY AND SATURDAY WITH INCREASED CLOUD AND PRECIP COVERAGE. LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 730 AM SUNDAY... WINDS WILL BE LIGHT THROUGH THE PERIOD...GENERALLY OUR OF THE WEST- SOUTHWEST. MID CLOUDS WILL TO STREAM IN FROM THE NORTHWEST...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF NC AS A DISTURBANCE CROSSES THE AREA. IFR/LIFR VSBYS DEVELOP FROM KFAY TO KRWI THIS MORNING BUT ARE ALREADY BEGINNING TO IMPROVE. VFR CONDITIONS SHOULD THUS RETURN BY 14Z AND CONTINUE THROUGH THE REMAINDER OF THE TAF PERIOD. OUTLOOK... BETTER CHANCES FOR SHOWERS AND STORMS LATE MONDAY WITH ANOTHER DISTURBANCE CROSSING THE REGION. THEN THE NEXT PERIOD O UNSETTLED WEATHER LOOKS TO COME LATE IN THE WEEK. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS NEAR TERM...VINCENT SHORT TERM...BLS LONG TERM...ELLIS AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EDT SUN AUG 17 2014 .SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES IN WEST-NORTHWESTERLY FLOW WILL CROSS THE REGION THIS WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM SUNDAY... WATER VAPOR AND RAP SHOW A WEAK DISTURBANCE MOVING FROM KENTUCKY INTO SOUTHWESTERN VIRGINIA..CAUSING SOME SOME RADAR ECHOES TO START SHOWING UP AS FAR SOUTH AS BOONE. RAP FORECAST SOUNDINGS SHOW ALMOST NO MUCAPE OVER CENTRAL NC AND RATHER DRY AIR BELOW 15K FT. MOST OF THE PRECIP WONT REACH THE GROUND...THROUGH A FEW SPRINKLES ARE POSSIBLE AS THE DISTURBANCE MOVES ACROSS THE AREA THIS MORNING....MAINLY NORTH OF HWY 64. OTHERWISE IT APPEARS THE CHANCES OF ANY SHOWERS OR STORMS THIS AFTERNOON WILL BE FAIRLY LIMITED DUE TO A PERIOD OF SUBSIDENCE THAT IS LIKELY BEHIND THE AFOREMENTIONED DISTURBANCE AND VERY WEAK INSTABILITY. BASED ON SATELLITE IMAGERY UPSTREAM...MID/HIGH CLOUDS WILL BE FAIRLY OPAQUE THIS MORNING...AND IF A BREAK DOESNT DEVELOP THIS AFTERNOON BEHIND THE UPPER DISTURBANCE...THEN FORECAST HIGHS MAY STILL BE TOO WARM. HAVE TRIMMED HIGHS BACK INTO HE UPPER 80S ACROSS THE NORTHERN PIEDMONT...WITH LOW/MID 90S TO THE SOUTH IN ACCORDANCE WITH MOS CONSENSUS. SHOULD CONTINUE TO SEE MID AND HIGH CLOUDS STREAMING IN FROM THE NORTHWEST AHEAD OF THE MCV CURRENTLY OVER THE STL AREA. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 AM SUNDAY... THE MCV CURRENTLY IN THE VICINITY OF KSTL...WHICH IS RATHER STRONG BASED ON SATELLITE PRESENTATION...IS FORECAST TO CROSS THE APPALACHIANS BY MIDDAY MONDAY....WITH A SHARPENING PIEDMONT TROUGH. GFS FORECAST SOUNDINGS GIVE 1000-2000 J/KG OF MLCAPE... HIGHER IN THE EAST WHERE HEATING WILL BE FAVORED AND LAPSE RATES STEEPEN THE MOST. PW INCREASES TO OVER 2 INCHES BY MONDAY AFTERNOON...AND COMBINED WITH THE FORCING AND INSTABILITY SHOULD SUPPORT SCATTERED STORMS. THE LARGER SCALE SHEAR IS EXPECTED TO BE RELATIVELY WEAK...20-25KT...THOUGH THE DISTURBANCE MAY AUGMENT SHEAR LOCALLY AS IT CROSSES THE AREA. HOWEVER...HIGH PW AND STEEP LOW-LEVEL LAPSE RATES MAY STILL CREATE THE POTENTIAL FOR A FEW STRONG WIND GUSTS. HIGHS 88-93. SHOULD SEE SOME CLEARING BEHIND THE UPPER DISTURBANCE ON MONDAY NIGHT AND THE POTENTIAL FOR SOME PATCHY FOG DEPENDING ON WHERE STORMS OCCUR. LOWS UPPER 60S TO LOWER 70S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 235 AM SUNDAY... TUESDAY AND TUESDAY NIGHT: TUESDAY WILL SEE A SHORTWAVE AND ASSOCIATED MESO-LOW MOVE THROUGH THE NORTHERN HALF OF THE CWA...ENDING UP NORTHEAST OF THE AREA BY TUESDAY AFTERNOON. THE ASSOCIATED DPVA MAXIMUM IS NOW TRACKING A LITTLE FURTHER SOUTH THAN PREVIOUS RUNS...ENDING UP BETWEEN KFAY AND KRWI BY 18Z TUESDAY. THIS IS CAUSING A VERY SMALL AMPLITUDE SHORTWAVE TROUGH AT 500MB THAT COULD CAUSE CONVECTION TO EXTEND FURTHER SOUTH ALONG THE I-95 CORRIDOR THAN ORIGINALLY THOUGHT ON TUESDAY AFTERNOON/EVENING. WILL RAISE POPS ACCORDINGLY...CLOSER TO 40 PERCENT IN THE EAST...WHILE MAINTAINING SLIGHT CHANCE IN THE WEST. MODEL FORECAST SOUNDINGS DURING THIS TIME INDICATE ABOUT 1000 J/KG OF CAPE AND BULK SHEAR NEAR 20 KTS. VERY STRONG LOW LEVEL LAPSE RATES HELPING TO CREATE INVERTED V SIGNATURES ON THE SOUNDINGS. CANT RULE OUT A SEVERE STORM OR TWO WITH DAMAGING WINDS THE MOST LIKELY SCENARIO BUT SOME SMALL HAIL ALSO POSSIBLE WITH GOOD CAPE IN THE HAIL GROWTH ZONE. WHILE HODOGRAPHS AT KRWI DO SHOW SOME CURVATURE IN THE LOWEST 3 KM...THE SHEAR MAGNITUDE IS VERY LOW AT LESS THAN 10 KTS AND THUS KEEPING HELICITY VALUES DOWN. THIS COUPLED WITH VERY HIGH LCL VALUES MAKES ANY TORNADIC THREAT UNLIKELY. SPC HAS THE AREA IN A GENERIC SEE TEXT FOR THE DAY 3 CONVECTIVE OUTLOOK AT THIS TIME. DUE TO AN INCREASE IN EXPECTED CLOUD COVER/PRECIPIATION COVERAGE...WILL LOWER MAX TEMPS IN THE EASTERN HALF OF THE CWA...UPPER 80S TO NEAR 90 AND MAINTAIN UPPER 80S TO LOW 90S IN THE WEST. EXPECT PRECIPIATION TO WIND DOWN OVERNIGHT TUESDAY AS LOW PULLS OFF TO THE NORTHEAST. LOWS IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH SATURDAY: THE CONFIDENCE IN THE FORECAST BEGINS TO DEGRADE SIGNIFICANTLY AS THE FORECAST PERIOD GOES ON AS MODELS BEGIN TO AMPLIFY A LONGWAVE TROUGH OVER THE EASTERN CONUS WITH STRONG HIGH PRESSURE OVER THE DEEP SOUTH AND INTO THE TEXARKANA REGION AND AN ASSOCIATED RIDGE EXTENDING UP INTO THE CENTRAL PLAINS. WHILE DETERMINISTIC MODELS AMPLIFY THE PATTERN STRONGLY...ENSEMBLE MEANS HAVE BEEN MORE CONSISTENT WITH A MORE MUTED SCENARIO. A SERIES OF SHORTWAVES WILL MARCH THROUGH THE UPPER TROUGH THROUGH SATURDAY MAKING PRECIPITATION POSSIBLE EACH DAY. TOTAL MOISTURE DROPS OFF WEDNESDAY AND THURSDAY MAKING THESE DAYS MORE LIKELY TO REMAIN DRY OR FOR CONVECTION TO BE MORE SCATTERED IN NATURE. A STRONGER SURGE OF MOISTURE RETURNS FOR FRIDAY AND SATURDAY. WILL MAINTAIN SLIGHT CHANCE POPS WEDNESDAY AND THURSDAY AFTERNOONS AND RAMP UP TO CHANCE FOR FRIDAY AND SATURDAY. HIGHS WEDNESDAY AND THURSDAY IN THE LOW 90S AND THEN DROPPING BACK TO THE UPPER 80S FOR FRIDAY AND SATURDAY WITH INCREASED CLOUD AND PRECIP COVERAGE. LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. && .AVIATION /06 SUNDAY THROUGH THURSDAY/... AS OF 130 AM SUNDAY... WINDS WILL BE LIGHT THROUGH THE PERIOD...GENERALLY OUR OF THE WEST- SOUTHWEST. MID CLOUDS WILL INCREASE...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF NC AS A DISTURBANCE CROSSES THE AREA...BUT THE CHANCES OF MORE THAN SPRINKLE SEEM LOW. PATCHY FOG SHOULD CONTINUE TO DEVELOP THIS MORNING..WITH A GOOD POSSIBILITY OF MVFR/IFR VSBYS ARE KFAY OR KRWI PRIOR TO 13Z.. OTHERWISE...VFR EXPECTED AT OTHER TAF SITES. OUTLOOK... BETTER CHANCES FOR SHOWERS AND STORMS LATE MONDAY WITH ANOTHER DISTURBANCE CROSSING THE REGION. THEN THE NEXT PERIOD O UNSETTLED WEATHER LOOKS TO COME LATE IN THE WEEK. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS NEAR TERM...BLS SHORT TERM...BLS LONG TERM...ELLIS AVIATION...BLS/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SUN AUG 17 2014 .SYNOPSIS...A CLIMATOLOGICAL SUMMER PATTERN WILL PREVAIL ACROSS THE REGION THROUGH THE REMAINDER OF THE WEEKEND. A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE CAROLINAS AND MID ATLANTIC EARLY TO MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM SUNDAY... WATER VAPOR AND RAP SHOW A WEAK DISTURBANCE MOVING FROM KENTUCKY INTO SOUTHWESTERN VIRGINIA..CAUSING SOME SOME RADAR ECHOES TO START SHOWING UP AS FAR SOUTH AS BOONE. RAP FORECAST SOUNDINGS SHOW ALMOST NO MUCAPE OVER CENTRAL NC AND RATHER DRY AIR BELOW 15K FT. MOST OF THE PRECIP WONT REACH THE GROUND...THROUGH A FEW SPRINKLES ARE POSSIBLE AS THE DISTURBANCE MOVES ACROSS THE AREA THIS MORNING....MAINLY NORTH OF HWY 64. OTHERWISE IT APPEARS THE CHANCES OF ANY SHOWERS OR STORMS THIS AFTERNOON WILL BE FAIRLY LIMITED DUE TO A PERIOD OF SUBSIDENCE THAT IS LIKELY BEHIND THE AFOREMENTIONED DISTURBANCE AND VERY WEAK INSTABILITY. BASED ON SATELLITE IMAGERY UPSTREAM...MID/HIGH CLOUDS WILL BE FAIRLY OPAQUE THIS MORNING...AND IF A BREAK DOESNT DEVELOP THIS AFTERNOON BEHIND THE UPPER DISTURBANCE...THEN FORECAST HIGHS MAY STILL BE TOO WARM. HAVE TRIMMED HIGHS BACK INTO HE UPPER 80S ACROSS THE NORTHERN PIEDMONT...WITH LOW/MID 90S TO THE SOUTH IN ACCORDANCE WITH MOS CONSENSUS. SHOULD CONTINUE TO SEE MID AND HIGH CLOUDS STREAMING IN FROM THE NORTHWEST AHEAD OF THE MCV CURRENTLY OVER THE STL AREA. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 PM SATURDAY... TO BE UPDATED SHORTLY... && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 235 AM SUNDAY... TUESDAY AND TUESDAY NIGHT: TUESDAY WILL SEE A SHORTWAVE AND ASSOCIATED MESO-LOW MOVE THROUGH THE NORTHERN HALF OF THE CWA...ENDING UP NORTHEAST OF THE AREA BY TUESDAY AFTERNOON. THE ASSOCIATED DPVA MAXIMUM IS NOW TRACKING A LITTLE FURTHER SOUTH THAN PREVIOUS RUNS...ENDING UP BETWEEN KFAY AND KRWI BY 18Z TUESDAY. THIS IS CAUSING A VERY SMALL AMPLITUDE SHORTWAVE TROUGH AT 500MB THAT COULD CAUSE CONVECTION TO EXTEND FURTHER SOUTH ALONG THE I-95 CORRIDOR THAN ORIGINALLY THOUGHT ON TUESDAY AFTERNOON/EVENING. WILL RAISE POPS ACCORDINGLY...CLOSER TO 40 PERCENT IN THE EAST...WHILE MAINTAINING SLIGHT CHANCE IN THE WEST. MODEL FORECAST SOUNDINGS DURING THIS TIME INDICATE ABOUT 1000 J/KG OF CAPE AND BULK SHEAR NEAR 20 KTS. VERY STRONG LOW LEVEL LAPSE RATES HELPING TO CREATE INVERTED V SIGNATURES ON THE SOUNDINGS. CANT RULE OUT A SEVERE STORM OR TWO WITH DAMAGING WINDS THE MOST LIKELY SCENARIO BUT SOME SMALL HAIL ALSO POSSIBLE WITH GOOD CAPE IN THE HAIL GROWTH ZONE. WHILE HODOGRAPHS AT KRWI DO SHOW SOME CURVATURE IN THE LOWEST 3 KM...THE SHEAR MAGNITUDE IS VERY LOW AT LESS THAN 10 KTS AND THUS KEEPING HELICITY VALUES DOWN. THIS COUPLED WITH VERY HIGH LCL VALUES MAKES ANY TORNADIC THREAT UNLIKELY. SPC HAS THE AREA IN A GENERIC SEE TEXT FOR THE DAY 3 CONVECTIVE OUTLOOK AT THIS TIME. DUE TO AN INCREASE IN EXPECTED CLOUD COVER/PRECIPIATION COVERAGE...WILL LOWER MAX TEMPS IN THE EASTERN HALF OF THE CWA...UPPER 80S TO NEAR 90 AND MAINTAIN UPPER 80S TO LOW 90S IN THE WEST. EXPECT PRECIPIATION TO WIND DOWN OVERNIGHT TUESDAY AS LOW PULLS OFF TO THE NORTHEAST. LOWS IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH SATURDAY: THE CONFIDENCE IN THE FORECAST BEGINS TO DEGRADE SIGNIFICANTLY AS THE FORECAST PERIOD GOES ON AS MODELS BEGIN TO AMPLIFY A LONGWAVE TROUGH OVER THE EASTERN CONUS WITH STRONG HIGH PRESSURE OVER THE DEEP SOUTH AND INTO THE TEXARKANA REGION AND AN ASSOCIATED RIDGE EXTENDING UP INTO THE CENTRAL PLAINS. WHILE DETERMINISTIC MODELS AMPLIFY THE PATTERN STRONGLY...ENSEMBLE MEANS HAVE BEEN MORE CONSISTENT WITH A MORE MUTED SCENARIO. A SERIES OF SHORTWAVES WILL MARCH THROUGH THE UPPER TROUGH THROUGH SATURDAY MAKING PRECIPITATION POSSIBLE EACH DAY. TOTAL MOISTURE DROPS OFF WEDNESDAY AND THURSDAY MAKING THESE DAYS MORE LIKELY TO REMAIN DRY OR FOR CONVECTION TO BE MORE SCATTERED IN NATURE. A STRONGER SURGE OF MOISTURE RETURNS FOR FRIDAY AND SATURDAY. WILL MAINTAIN SLIGHT CHANCE POPS WEDNESDAY AND THURSDAY AFTERNOONS AND RAMP UP TO CHANCE FOR FRIDAY AND SATURDAY. HIGHS WEDNESDAY AND THURSDAY IN THE LOW 90S AND THEN DROPPING BACK TO THE UPPER 80S FOR FRIDAY AND SATURDAY WITH INCREASED CLOUD AND PRECIP COVERAGE. LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. && .AVIATION /06 SUNDAY THROUGH THURSDAY/... AS OF 130 AM SUNDAY... WINDS WILL BE LIGHT THROUGH THE PERIOD...GENERALLY OUR OF THE WEST- SOUTHWEST. MID CLOUDS WILL INCREASE...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF NC AS A DISTURBANCE CROSSES THE AREA...BUT THE CHANCES OF MORE THAN SPRINKLE SEEM LOW. PATCHY FOG SHOULD CONTINUE TO DEVELOP THIS MORNING..WITH A GOOD POSSIBILITY OF MVFR/IFR VSBYS ARE KFAY OR KRWI PRIOR TO 13Z.. OTHERWISE...VFR EXPECTED AT OTHER TAF SITES. OUTLOOK... BETTER CHANCES FOR SHOWERS AND STORMS LATE MONDAY WITH ANOTHER DISTURBANCE CROSSING THE REGION. THEN THE NEXT PERIOD O UNSETTLED WEATHER LOOKS TO COME LATE IN THE WEEK. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BLS SHORT TERM...VINCENT LONG TERM...ELLIS AVIATION...BLS/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 AM EDT SUN AUG 17 2014 .SYNOPSIS...A CLIMATOLOGICAL SUMMER PATTERN WILL PREVAIL ACROSS THE REGION THROUGH THE REMAINDER OF THE WEEKEND. A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS THE CAROLINAS AND MID ATLANTIC EARLY TO MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10 PM SATURDAY... ISOLATED TO SCATTERED CONVECTION ACROSS THE SOUTHERN/SOUTHEASTERN HALF OF THE AREA HAS DISSIPATED WITH THE LOSS OF DAYTIME HEATING THIS EVENING AND WEAK S/W ENERGY ALOFT PUSHING TO THE EAST/SOUTH OF THE AREA. ONLY ADDITIONAL WEAK PERTURBATIONS ARE EXPECTED TO TRACK ACROSS CENTRAL NC OVERNIGHT IN THE WNW FLOW ALOFT... WITH MODELS GENERALLY INDICATING DRY CONDITIONS OVERNIGHT. HOWEVER... THE LATEST RUC AND HRRR ARE SHOWING THE POTENTIAL FOR INCREASING MID AND HIGH LEVEL CLOUD COVER IN ADVANCE OF MORE PRONOUNCED S/W ENERGY CURRENTLY OVER MO/IL/IN/KY... AN PERHAPS EVEN GENERATING SOME SPRINKLES ACROSS THE NORTHWEST PIEDMONT BY AROUND DAYBREAK. IN ADDITION... DEPENDING ON THE AMOUNT OF MID AND HIGH LEVEL CLOUD COVER WE COULD SEE SOME PATCHY FOG OVERNIGHT THANKS TO THE SPOTTY HEAVY RAIN EARLIER TODAY ACROSS SOUTHERN PORTIONS OF THE AREA (AND WHERE THE HIGHEST SURFACE DEWPOINTS RESIDE). OVERNIGHT LOWS ARE EXPECTED TO RANGE FROM THE MID TO UPPER 60S NORTH/NORTHWEST TO THE LOWER 70S SOUTH. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 330 PM SATURDAY... WNW FLOW ALOFT WILL PERSIST OVER THE CAROLINAS THROUGH SUNDAY NIGHT. A COMPACT UPPER LOW CENTERED IN NORTHERN MO/SOUTHERN IA THIS AFTERNOON WILL TRACK THROUGH SOUTHERN IL/IN TONIGHT...INTO THE TN VALLEY ON SUNDAY...AND THE WINDWARD SLOPES OF THE SOUTHERN APPALACHIANS SUNDAY NIGHT. 12Z MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE EVOLUTION (I.E. TIMING/LOCATION) OF THIS FEATURE...SUGGESTING THAT IT SHOULD HAVE LITTLE INFLUENCE ON FORCING FOR ASCENT IN CENTRAL NC PRIOR TO EARLY MONDAY MORNING. HOWEVER...TRANSIENT DPVA IS EXPECTED IN ASSOC/W PROGRESSIVE SMALL AMPLITUDE DISTURBANCES TRACKING ACROSS THE REGION IN WNW FLOW ALOFT SUN/SUN NIGHT... POSSIBLY INCLUDING MID-LEVEL VORTICITY MAXIMA SPAWNED BY UPSTREAM MCS ACTIVITY. STRONG INSOLATION WILL YIELD HIGHS IN THE LOWER TO MID 90S OR 90-95F SUNDAY...PERHAPS A DEGREE OR TWO LOWER IF BROKEN MID- LEVEL CLOUD COVER IS PRESENT. MODEL GUIDANCE VARIES W/REGARD TO DEGREE OF DESTABILIZATION SUN AFTERNOON...THOUGH AGREES ON THE GENERAL TREND OF LOWER INSTABILITY W/NW AND HIGHER E/SE. GIVEN A WEAK MSLP PATTERN...THE LACK OF A LOW-LEVEL FOCUS (OUTSIDE OF THE SEABREEZE)...DIFFICULTY IN ASSESSING THE PRECISE EVOLUTION OF PROGRESSIVE SMALL AMPLITUDE DISTURBANCES ALOFT...AND UNCERTAINTY IN THE DEGREE OF DESTABILIZATION...HAVE OPTED TO LEAVE CHANCES FOR CONVECTION AT 20%. LOWS SUN NIGHT WILL BE SLIGHTLY WARMER THAN TONIGHT...IN THE UPPER 60S TO LOWER 70S. -VINCENT && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 235 AM SUNDAY... TUESDAY AND TUESDAY NIGHT: TUESDAY WILL SEE A SHORTWAVE AND ASSOCIATED MESO-LOW MOVE THROUGH THE NORTHERN HALF OF THE CWA...ENDING UP NORTHEAST OF THE AREA BY TUESDAY AFTERNOON. THE ASSOCIATED DPVA MAXIMUM IS NOW TRACKING A LITTLE FURTHER SOUTH THAN PREVIOUS RUNS...ENDING UP BETWEEN KFAY AND KRWI BY 18Z TUESDAY. THIS IS CAUSING A VERY SMALL AMPLITUDE SHORTWAVE TROUGH AT 500MB THAT COULD CAUSE CONVECTION TO EXTEND FURTHER SOUTH ALONG THE I-95 CORRIDOR THAN ORIGINALLY THOUGHT ON TUESDAY AFTERNOON/EVENING. WILL RAISE POPS ACCORDINGLY...CLOSER TO 40 PERCENT IN THE EAST...WHILE MAINTAINING SLIGHT CHANCE IN THE WEST. MODEL FORECAST SOUNDINGS DURING THIS TIME INDICATE ABOUT 1000 J/KG OF CAPE AND BULK SHEAR NEAR 20 KTS. VERY STRONG LOW LEVEL LAPSE RATES HELPING TO CREATE INVERTED V SIGNATURES ON THE SOUNDINGS. CANT RULE OUT A SEVERE STORM OR TWO WITH DAMAGING WINDS THE MOST LIKELY SCENARIO BUT SOME SMALL HAIL ALSO POSSIBLE WITH GOOD CAPE IN THE HAIL GROWTH ZONE. WHILE HODOGRAPHS AT KRWI DO SHOW SOME CURVATURE IN THE LOWEST 3 KM...THE SHEAR MAGNITUDE IS VERY LOW AT LESS THAN 10 KTS AND THUS KEEPING HELICITY VALUES DOWN. THIS COUPLED WITH VERY HIGH LCL VALUES MAKES ANY TORNADIC THREAT UNLIKELY. SPC HAS THE AREA IN A GENERIC SEE TEXT FOR THE DAY 3 CONVECTIVE OUTLOOK AT THIS TIME. DUE TO AN INCREASE IN EXPECTED CLOUD COVER/PRECIPIATION COVERAGE...WILL LOWER MAX TEMPS IN THE EASTERN HALF OF THE CWA...UPPER 80S TO NEAR 90 AND MAINTAIN UPPER 80S TO LOW 90S IN THE WEST. EXPECT PRECIPIATION TO WIND DOWN OVERNIGHT TUESDAY AS LOW PULLS OFF TO THE NORTHEAST. LOWS IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH SATURDAY: THE CONFIDENCE IN THE FORECAST BEGINS TO DEGRADE SIGNIFICANTLY AS THE FORECAST PERIOD GOES ON AS MODELS BEGIN TO AMPLIFY A LONGWAVE TROUGH OVER THE EASTERN CONUS WITH STRONG HIGH PRESSURE OVER THE DEEP SOUTH AND INTO THE TEXARKANA REGION AND AN ASSOCIATED RIDGE EXTENDING UP INTO THE CENTRAL PLAINS. WHILE DETERMINISTIC MODELS AMPLIFY THE PATTERN STRONGLY...ENSEMBLE MEANS HAVE BEEN MORE CONSISTENT WITH A MORE MUTED SCENARIO. A SERIES OF SHORTWAVES WILL MARCH THROUGH THE UPPER TROUGH THROUGH SATURDAY MAKING PRECIPITATION POSSIBLE EACH DAY. TOTAL MOISTURE DROPS OFF WEDNESDAY AND THURSDAY MAKING THESE DAYS MORE LIKELY TO REMAIN DRY OR FOR CONVECTION TO BE MORE SCATTERED IN NATURE. A STRONGER SURGE OF MOISTURE RETURNS FOR FRIDAY AND SATURDAY. WILL MAINTAIN SLIGHT CHANCE POPS WEDNESDAY AND THURSDAY AFTERNOONS AND RAMP UP TO CHANCE FOR FRIDAY AND SATURDAY. HIGHS WEDNESDAY AND THURSDAY IN THE LOW 90S AND THEN DROPPING BACK TO THE UPPER 80S FOR FRIDAY AND SATURDAY WITH INCREASED CLOUD AND PRECIP COVERAGE. LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S. && .AVIATION /06 SUNDAY THROUGH THURSDAY/... AS OF 130 AM SUNDAY... WINDS WILL BE LIGHT THROUGH THE PERIOD...GENERALLY OUR OF THE WEST- SOUTHWEST. MID CLOUDS WILL INCREASE...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF NC AS A DISTURBANCE CROSSES THE AREA...BUT THE CHANCES OF MORE THAN SPRINKLE SEEM LOW. PATCHY FOG SHOULD CONTINUE TO DEVELOP THIS MORNING..WITH A GOOD POSSIBILITY OF MVFR/IFR VSBYS ARE KFAY OR KRWI PRIOR TO 13Z.. OTHERWISE...VFR EXPECTED AT OTHER TAF SITES. OUTLOOK... BETTER CHANCES FOR SHOWERS AND STORMS LATE MONDAY WITH ANOTHER DISTURBANCE CROSSING THE REGION. THEN THE NEXT PERIOD O UNSETTLED WEATHER LOOKS TO COME LATE IN THE WEEK. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BSD SHORT TERM...VINCENT LONG TERM...ELLIS AVIATION...BLS/CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
935 PM CDT MON AUG 18 2014 .UPDATE... ISSUED AT 935 PM CDT MON AUG 18 2014 NO SIGNIFICANT UPDATES THIS EVENING. PRECIPITATION HAS ALL BUT ENDED OVER EASTERN NORTH DAKOTA...THUS CLEAR TO PARTLY CLOUDY SKIES EXPECTED TONIGHT WITH PATCHY FOG POSSIBLE AFTER MIDNIGHT. CURRENT FORECAST LOWS IN THE 50S LOOK REASONABLE. UPDATE ISSUED AT 638 PM CDT MON AUG 18 2014 ISOLATED THUNDERSHOWERS CONTINUE TO DISSIPATE ACROSS EASTERN PORTIONS OF CENTRAL NORTH DAKOTA. HAVE REMOVED ALL EVENING POPS EXCEPT FOR JUST A SLIGHT CHANCE FAR EAST THROUGH 9 PM. OTHERWISE MOSTLY CLEAR SKIES TONIGHT WITH LIGHT WINDS. PREVIOUS FORECAST HAD A MENTION OF PATCHY FOG AFTER MIDNIGHT...WHICH LOOKS GOOD. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 DIURNAL CONVECTION THROUGH SUNSET THIS EVENING AND FOG TONIGHT HIGHLIGHT THE SHORT TERM. DIURNAL SCATTERED CONVECTION IS EXPECTED TO REMAIN FOCUSED ACROSS THE SOUTH CENTRAL AND JAMES RIVER VALLEY GIVEN RADAR AND SATELLITE TRENDS THROUGH 1930 UTC...AND THE 16-17 UTC HRRR ITERATIONS. MODEST INSTABILITY AND WEAK SHEAR ARE EXPECTED TO KEEP STORMS BELOW SEVERE LIMITS. HOWEVER...THE NON SUPERCELL TORNADO OR LANDSPOUT PARAMETER HAS A LOCAL MAXIMA ACROSS THE JAMES RIVER VALLEY INTO THE SOUTHERN RED RIVER VALLEY WITH STEEP LOW LEVEL LAPSE RATES AND ENVIRONMENTAL VORTICITY. THUS...WOULD NOT BE SURPRISED BY A FUNNEL CLOUD REPORT. FOR TONIGHT...WITH WEAK SURFACE HIGH PRESSURE IN PLACE...CLEAR SKIES...LIGHT WINDS AND PLENTIFUL MOISTURE FROM WEEKEND RAINS...AREAS OF FOG ARE POSSIBLE ACROSS MUCH OF THE AREA TONIGHT. TUESDAY WILL BE THE ONLY DRY DAY IN THE FORECAST UNDER SHORTWAVE RIDGING BEFORE A RETURN TO AN ACTIVE WEATHER PATTERN THROUGH THE EXTENDED. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 A SLOW MOVING TROUGH EXTENDING FROM THE NORTHWEST TERRITORIES WILL PRODUCE CHANCES FOR WIDESPREAD SHOWERS/THUNDERSTORMS FROM WEDNESDAY INTO THE WEEKEND. CHANCES FOR PRECIPITATION WILL CONTINUE THROUGH THE EXTENDED...AS UNSETTLED SOUTHWESTERLY FLOW REMAINS OVER THE AREA. HEAVY RAINFALL IS EXPECTED OVER WESTERN AND CENTRAL PORTIONS OF THE STATE WEDNESDAY INTO THURSDAY...WITH ADDITIONAL RAINFALL THROUGH THE WEEKEND. WESTERN AND CENTRAL AREAS HAVE ALREADY BEEN SATURATED WITH ABUNDANT RAINFALL...FLOODING ISSUES REMAIN A CONCERN. TEMPERATURES WILL NEAR AVERAGE FOR WEDNESDAY AND THURSDAY. A COOLER AIRMASS BEGINS MOVING INTO THE AREA BY FRIDAY MORNING...HIGHS WILL RANGE BETWEEN 10 AND 15 DEGREES BELOW AVERAGE THROUGH THE REST OF THE PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 935 PM CDT MON AUG 18 2014 FOR THE MOST PART...EXPECT VFR CONDITIONS AT ALL TAF SITES THROUGH THE 00 UTC TAF PERIOD. COULD SEE SOME PATCHY FOG EARLY TUESDAY MORNING GIVEN THE LIGHT WINDS AND CLEAR SKIES...AND THE RECENT RAINS. HOWEVER...NOT CONFIDENT ENOUGH TO MENTION AT AERODROMES EXCEPT FOR A VCFG FROM 09-13 UTC AT KJMS WHERE DEWPOINT DEPRESSIONS ARE EXPECTED TO BE LOWEST. NORTHWEST WINDS WILL DIMINISH QUICKLY THIS EVENING WITH LIGHT WINDS OVERNIGHT. SURFACE FLOW WILL SHIFT SOUTHERLY FROM WEST TO EAST ON TUESDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...AYD LONG TERM...AC AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
638 PM CDT MON AUG 18 2014 .UPDATE... ISSUED AT 638 PM CDT MON AUG 18 2014 ISOLATED THUNDERSHOWERS CONTINUE TO DISSIPATE ACROSS EASTERN PORTIONS OF CENTRAL NORTH DAKOTA. HAVE REMOVED ALL EVENING POPS EXCEPT FOR JUST A SLIGHT CHANCE FAR EAST THROUGH 9 PM. OTHERWISE MOSTLY CLEAR SKIES TONIGHT WITH LIGHT WINDS. PREVIOUS FORECAST HAD A MENTION OF PATCHY FOG AFTER MIDNIGHT...WHICH LOOKS GOOD. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 DIURNAL CONVECTION THROUGH SUNSET THIS EVENING AND FOG TONIGHT HIGHLIGHT THE SHORT TERM. DIURNAL SCATTERED CONVECTION IS EXPECTED TO REMAIN FOCUSED ACROSS THE SOUTH CENTRAL AND JAMES RIVER VALLEY GIVEN RADAR AND SATELLITE TRENDS THROUGH 1930 UTC...AND THE 16-17 UTC HRRR ITERATIONS. MODEST INSTABILITY AND WEAK SHEAR ARE EXPECTED TO KEEP STORMS BELOW SEVERE LIMITS. HOWEVER...THE NON SUPERCELL TORNADO OR LANDSPOUT PARAMETER HAS A LOCAL MAXIMA ACROSS THE JAMES RIVER VALLEY INTO THE SOUTHERN RED RIVER VALLEY WITH STEEP LOW LEVEL LAPSE RATES AND ENVIRONMENTAL VORTICITY. THUS...WOULD NOT BE SURPRISED BY A FUNNEL CLOUD REPORT. FOR TONIGHT...WITH WEAK SURFACE HIGH PRESSURE IN PLACE...CLEAR SKIES...LIGHT WINDS AND PLENTIFUL MOISTURE FROM WEEKEND RAINS...AREAS OF FOG ARE POSSIBLE ACROSS MUCH OF THE AREA TONIGHT. TUESDAY WILL BE THE ONLY DRY DAY IN THE FORECAST UNDER SHORTWAVE RIDGING BEFORE A RETURN TO AN ACTIVE WEATHER PATTERN THROUGH THE EXTENDED. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 A SLOW MOVING TROUGH EXTENDING FROM THE NORTHWEST TERRITORIES WILL PRODUCE CHANCES FOR WIDESPREAD SHOWERS/THUNDERSTORMS FROM WEDNESDAY INTO THE WEEKEND. CHANCES FOR PRECIPITATION WILL CONTINUE THROUGH THE EXTENDED...AS UNSETTLED SOUTHWESTERLY FLOW REMAINS OVER THE AREA. HEAVY RAINFALL IS EXPECTED OVER WESTERN AND CENTRAL PORTIONS OF THE STATE WEDNESDAY INTO THURSDAY...WITH ADDITIONAL RAINFALL THROUGH THE WEEKEND. WESTERN AND CENTRAL AREAS HAVE ALREADY BEEN SATURATED WITH ABUNDANT RAINFALL...FLOODING ISSUES REMAIN A CONCERN. TEMPERATURES WILL NEAR AVERAGE FOR WEDNESDAY AND THURSDAY. A COOLER AIRMASS BEGINS MOVING INTO THE AREA BY FRIDAY MORNING...HIGHS WILL RANGE BETWEEN 10 AND 15 DEGREES BELOW AVERAGE THROUGH THE REST OF THE PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 638 PM CDT MON AUG 18 2014 FOR THE MOST PART...EXPECT VFR CONDITIONS AT ALL TAF SITES THROUGH THE 00 UTC TAF PERIOD. COULD SEE SOME PATCHY FOG EARLY TUESDAY MORNING GIVEN THE LIGHT WINDS AND CLEAR SKIES...AND THE RECENT RAINS. HOWEVER...NOT CONFIDENT ENOUGH TO MENTION AT AERODROMES EXCEPT FOR A VCFG FROM 09-13 UTC AT KJMS WHERE DEWPOINT DEPRESSIONS ARE EXPECTED TO BE LOWEST. NORTHWEST WINDS WILL DIMINISH QUICKLY THIS EVENING WITH LIGHT WINDS OVERNIGHT. SURFACE FLOW WILL SHIFT SOUTHERLY FROM WEST TO EAST ON TUESDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...AYD LONG TERM...AC AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1259 PM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1256 PM CDT SUN AUG 17 2014 THE NEWEST HIGH RESOLUTION MODELING...NAMELY THE 12 UTC WRF-ARW AND NMM AND THE 15 AND 16 UTC HRRR INITIATE CONVECTION A BIT FURTHER EAST THEN THEIR PREVIOUS ITERATIONS AND ADJUSTED POPS ACCORDINGLY. SEE SPC DAY ONE OUTLOOK FOR OVERALL DETAILS. UPDATE ISSUED AT 1011 AM CDT SUN AUG 17 2014 NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. THE 12 UTC NAM AND 10-11 UTC HRRR ITERATIONS CONTINUE THE TREND OF THE 00 UTC WRF-ARW AND NMM OF INITIATING POSSIBLY SEVERE CONVECTION ALONG A SURFACE TROUGH ACROSS WESTERN NORTH DAKOTA JUST EAST OF HIGHWAY 85 AROUND 20 UTC...PROPAGATING EAST INTO THE LATE AFTERNOON AND EVENING. THE 14 UTC RAP FORECASTS A MESOSCALE ENVIRONMENT CHARACTERIZED BY DEEP LAYER SHEAR OF 25-30KTS AND ML CAPE OF 1500-2000 J/KG...SUPPORTIVE OF POSSIBLE SUPERCELLS WITH LARGE HAIL BEING THE PRIMARY THREAT. RATHER WEAK LOW LEVEL SHEAR DOES DIMINISH THE TORNADIC THREAT. WILL HAVE TO CLOSELY MONITOR RAINFALL...ESPECIALLY FOR THOSE LOCATIONS HEAVILY IMPACTED ON SATURDAY. UPDATE ISSUED AT 625 AM CDT SUN AUG 17 2014 PRECIPITATION OVER FAR SOUTHWESTERN NORTH DAKOTA CONTINUES TO DISSIPATE AS IT MOVES EAST...WHICH IS REFLECTED WELL IN ONGOING POPS. SOME PATCHY FOG CONTINUES TO LOITER AROUND THE CWA...AND WILL CONTINUE THRU THE EARLY MORNING. UPDATES HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM CDT SUN AUG 17 2014 HYDROLOGY AND THE RISK FOR SEVERE THUNDERSTORMS RULE THE SHORT TERM. ADVISORIES FOR FLOODING HAVE ALL BEEN ALLOWED TO EXPIRE BASED ON REPORTS FROM LAW ENFORCEMENT AND THE LACK OF RAIN OVER THE PAST EIGHT HOURS OR SO IN THOSE ADVISORY AREAS. HYDROLOGIC OUTLOOKS HAVE BEEN ISSUED FOR THE APPLE CREEK IN BURLEIGH COUNTY...AND THE KNIFE RIVER BASIN...MAINLY THROUGH MERCER COUNTY. APPLE CREEK WAS PERFORMING WELL BELOW EXPECTATIONS WHILE THE KNIFE LOOKS LIKE IT WILL APPROACH MINOR FLOOD STAGE BUT MAY NOT MAKE IT TO THAT DEFINED FLOOD LEVEL. WILL BE REMOVING A FEW WESTERN COUNTIES FROM THE FLOOD WARNING IN THE CENTRAL PART OF WESTERN NORTH DAKOTA...AND LIKELY EXTENDING IN TIME THROUGH SUNDAY THE EASTERN PART OF THAT WARNING. HIGH RESOLUTION MODELS DEVELOP THUNDERSTORMS IN EASTERN MONTANA AND BRING THEM THROUGH WESTERN AND CENTRAL NORTH DAKOTA THIS AFTERNOON IN RESPONSE TO A MID LEVEL SHORT WAVE APPROACHING...AND THE CUT OFF MID LEVEL COOL POOL OVER SOUTHERN SASKATCHEWAN INCREASING DEEP LAYER SHEAR. INSTABILITY AND CAPE BECOME SUPPORTIVE OF SEVERE WEATHER ESPECIALLY BETWEEN 2 PM CDT AND 7 PM CDT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 420 AM CDT SUN AUG 17 2014 LOW/TROF CONTINUES ITS EASTWARD PROGRESSION INTO MONDAY WITH PRECIP CONTINUING TO TAPER FROM WEST TO EAST IN THE MORNING. IN THE AFTERNOON...SOME RE-DEVELOPMENT MAY OCCUR AS THE AREA REMAINS UNDER CYCLONIC FLOW...THOUGH MOST LOCATIONS SHOULD DRY OUT BY EVENING. A SHORT LIVED DRY PERIOD IS EXPECTED THROUGH THE DAY ON TUESDAY AS A FAST MOVING SHORT WAVE RIDGE MOVES THROUGH THE AREA. UPPER FLOW STARTS TO SHIFT SOUTHWESTERLY TUESDAY EVENING AS RIDGE PUSHES EAST AND TROF OVER THE WESTERN CONUS DEEPENS. CHANCES FOR PRECIPITATION THEN STEADILY INCREASE THROUGH MID-WEEK AS A VARIETY OF WAVES MOVE THROUGH THE FLOW...WITH THE GREATEST CHANCES COMING LATE WEDNESDAY AS A SFC LOW/BOUNDARY SHIFTS THROUGH THE AREA. MODELS THEN HAVING TROUBLE WITH THE TIMING OF INDIVIDUAL SYSTEMS FOR THE END OF THE WEEK...BUT GENERAL CONSENSUS IS AN ACTIVE PATTERN SO WILL KEEP POPS IN THE FORECAST. NEAR AVERAGE TEMPS EXPECTED THROUGH MID-WEEK WITH MODELS ADVERTISING A COOLING TREND FOR THE END OF THE WEEK/WEEKEND. WILL HAVE TO KEEP AN EYE ON THIS TO SEE HOW SIGNIFICANT OF A COOL DOWN THIS WILL BE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1256 PM CDT SUN AUG 17 2014 A LINE OF POSSIBLY SEVERE THUNDERSTORMS IS FORECAST TO DEVELOP ACROSS WESTERN NORTH DAKOTA AROUND 20 UTC...AND MOVE EAST THROUGH THE EVENING. SEE TAFS FOR EXPECTED TIMING AND IMPACTS TO EACH TERMINAL. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...JPM LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1225 PM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1225 PM CDT SUN AUG 17 2014 MADE SOME ADDITIONAL ADJUSTMENTS TO POPS...AS MOST OF THE CURRENT PRECIP HAS MOVED EAST OF THE CWA EXCEPT FOR SMALL AREAS IN THE NORTHERN RED RIVER VALLEY AND THE FAR SOUTH. WILL KEEP THE DOWNWARD TREND FOR THE REST OF THE DAY FOR THE PRECIP IN THE EAST...BUT RAMP UP POPS IN THE WEST THIS AFTERNOON AS THE SFC TROUGH AXIS MOVES INTO THE REGION. UPDATE ISSUED AT 1006 AM CDT SUN AUG 17 2014 SHOWERS CONTINUE TO DEVELOP OVER THE RED RIVER VALLEY AS THE WEAK UPPER LOW CONTINUES ON ONLY SLOWLY PULL EASTWARD. THESE SHOWERS SHOULD CONTINUE INTO OUR MN COUNTIES FOR THE REST OF THE MORNING AND SHOULD BE OUT OF THE CWA BY LATER IN THE AFTERNOON. THE MAIN UPPER TROUGH CONTINUES TO MOVE SLOWLY THROUGH THE NORTHERN ROCKIES...AND MODELS CONTINUE TO BE PRETTY BULLISH ON BREAKING OUT PRECIP AS THE TROUGH COMES THROUGH. THERE HAS BEEN A FASTER TREND...WITH THE RAP BRINGING THE PRECIP INTO THE RED RIVER VALLEY BY THIS EVENING AND LEAVING THE WESTERN COUNTIES DRY. THE WRF AND NAM ARE NOT QUITE AS FAST...AND GIVEN THE FAIRLY SLOW PROGRESSION OF THE TROUGH AND THE FACT THAT CONVECTION HAS NOT DEVELOPED YET...WILL LEAN TOWARDS THE NAM. SPED UP POPS A BIT THROUGH THIS AFTERNOON AND TONIGHT...BUT CONTINUED THE TREND OF KEEPING US FAIRLY WET THROUGH THE NIGHT. UPDATE ISSUED AT 710 AM CDT SUN AUG 17 2014 WATER VAPOR SHOWS THE 500 MB LOW/VORT HAS INCHED EAST AND WAS IN THE WHEATON MN AREA. GOT CLUSTERS OF SHOWERS AND A FEW STORMS NORTH AND EAST-SOUTHEAST OF SYSTEM OVER WEST CENTRAL-CENTRAL MN THEN BACK INTO SOUTHEASTERN ND. EXPECT ONLY SLOW MOVEMENT OF ENTIRE SYSTEM EAST TODAY. DID UPDATE WESTERN EDGE OF POPS TO INCREASE A BIT IN FARGO-LISBON AREA. ISOLATED SHOWERS IN THE NRN RRV. OTHERWISE 06Z MODEL RUNS SHOW MAIN ACTION MID AFTN IN WRN- CNTRL ND AS A BROKEN LINE OF STORMS FORMS ESTEVAN SK TO WEST OF BISMARCK AND STARTS TO MOVE EAST. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 350 AM CDT SUN AUG 17 2014 UPPER LEVEL LOW/VORT SEEN VERY SLOWLY DRIFTING EAST-NORTHEAST ALONG THE SD/ND BORDER NORTHEAST OF ABERDEEN EARLY THIS MORNING. CONVECTION WTIH THIS FEATURE WANED A BIT SINCE MIDNIGHT AS CLOUD TOPS WARMED WITH SOME NEW CONVECTION FIRING A BIT SOUTH BUT RADAR HAS SHOWN SOME NEW CONVECTION LAST 30 MIN IN FORMAN ND AREA. OVERALL EXPECT THIS SYSTEM TO SLOWLY MOVE EAST-NORTHEAST TODAY WITH MAIN POPS HOLDING IN REGION FROM BEMIDJI-ADA-FARGO-LISBON AREA SOUTHWARD. DID HOWEVER SPREAD SOME LOWER POPS NORTH AS A FEW VERY LIGHT SHOWERS HAVE BEEN ON RADAR DRIFTING EAST BTWN GFK-DVL UP TOWARD WEST OF LANGDON. SHORT RANGE MODELS NOT DOING TOO WELL WITH PRECIP CURRENTLY THRU TODAY. MOST DRIFT MAIN RAIN A BIT TOO FAR NORTH TODAY I BELIEVE. PWATS ARE HIGHEST EARLY ON TODAY BUT DO SLOWLY DECREASE A LITTLE AS DAY PROGRESSES AND SYSTEM SLOWLY MOVES EAST. OUTSIDE OF THIS SYSTEM LOOKS QUIET OVER WRN FCST BALANCE OF TODAY. NEXT SHORT WAVE TROUGH ENTERING WRN ND THIS AFTN AND TSTMS WILL FORM AND SPC HAS A SLIGHT RISK OF SVR WEST OF FCST AREA WITH MU CAPES IN THE 2-3K J/KG RANGE. SHORT WAVE TROUGH DOES MOVE EAST AND INTO THE RRV TOWARD 12Z MON AND THEN EAST THRU NW MINNESOTA MONDAY. KEPT IDEA OF LIKELY POPS SPREADING INTO ERN ND MOSTLY MID EVENIGN SPREADING INTO MN FCST AREA MONDAY. HPC QPF VALUES HAVE DROPPED WITH HPC FCSTS OF A GENERAL HALF INCH TO THREE QUARTERS OF AN INCH. FOR TEMPS...WITH CLOUDS HOLDING IN MOST AREAS TODAY NOT EXPECTING A HUGE RISE WITH MOSTLY 70S THOUGH IF ENOUGH SUN AROUND 80 PSBL IN THE WEST. 70S AGAIN MONDAY WITH CLOUDS. WITH CLOUDS HOLDING...FOG LOOKS A BIT LESS CERTAIN AND THUS SCALED BACK A BIT. NARROW CLEARING ZONE MORE IN ERN WFO BIS FCST AREA. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 350 AM CDT SUN AUG 17 2014 500 MB TROUGH WILL EXIT ERN MN MONDAY NIGHT WITH SHOWER THREAT ENDING. THEN HIGH PRESSURE BUILDS IN TUESDAY. TEMPS HOLDING NR NORMAL. WEDNESDAY-SATURDAY...DURING THIS TIME PERIOD THE SYNOPTIC FLOW PATTERN WILL BE IN TRANSITION TO A WESTERN US TROUGH AND DOWNSTREAM RIDGE...ALTHOUGH VARIOUS MODEL RUNS HAVE SHOWN DIFFERENCES IN THE ORIENTATION OF THIS PATTERN. EITHER WAY...INITIALLY QUIET WEATHER IS EXPECTED TO TREND MORE UNSETTLED LATER IN THE WEEK AS THE UPPER FLOW BECOMES MORE WESTERLY OR SOUTHWESTERLY OVER THE AREA. THERE IS STILL RATHER LOW CONFIDENCE ON THE TIMING OF INDIVIDUAL DISTURBANCES...AND THUS WHEN RAIN CHANCES WILL BE GREATEST. TEMPS WILL CONTINUE TO RUN WITHIN SEVERAL DEGREES OF AVERAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1225 PM CDT SUN AUG 17 2014 MVFR/IFR CIGS WILL ADVECT EASTWARD THROUGH THE AFTERNOON HOURS...AND THERE SHOULD BE A PERIOD OF MOSTLY CLEAR SKY THIS EVENING. USED THE LATEST HRRR/RAP FOR TIMING GUIDANCE. THE NEXT CONCERN WILL BE THUNDERSTORM CHANCES MOVING THROUGH THE REGION LATER THIS EVENING AND OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...RIDDLE LONG TERM...MAKOWSKI/RIDDLE AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1013 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1011 AM CDT SUN AUG 17 2014 NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. THE 12 UTC NAM AND 10-11 UTC HRRR ITERATIONS CONTINUE THE TREND OF THE 00 UTC WRF-ARW AND NMM OF INITIATING POSSIBLY SEVERE CONVECTION ALONG A SURFACE TROUGH ACROSS WESTERN NORTH DAKOTA JUST EAST OF HIGHWAY 85 AROUND 20 UTC...PROPAGATING EAST INTO THE LATE AFTERNOON AND EVENING. THE 14 UTC RAP FORECASTS A MESOSCALE ENVIRONMENT CHARACTERIZED BY DEEP LAYER SHEAR OF 25-30KTS AND ML CAPE OF 1500-2000 J/KG...SUPPORTIVE OF POSSIBLE SUPERCELLS WITH LARGE HAIL BEING THE PRIMARY THREAT. RATHER WEAK LOW LEVEL SHEAR DOES DIMINISH THE TORNADIC THREAT. WILL HAVE TO CLOSELY MONITOR RAINFALL...ESPECIALLY FOR THOSE LOCATIONS HEAVILY IMPACTED ON SATURDAY. UPDATE ISSUED AT 625 AM CDT SUN AUG 17 2014 PRECIPITATION OVER FAR SOUTHWESTERN NORTH DAKOTA CONTINUES TO DISSIPATE AS IT MOVES EAST...WHICH IS REFLECTED WELL IN ONGOING POPS. SOME PATCHY FOG CONTINUES TO LOITER AROUND THE CWA...AND WILL CONTINUE THRU THE EARLY MORNING. UPDATES HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM CDT SUN AUG 17 2014 HYDROLOGY AND THE RISK FOR SEVERE THUNDERSTORMS RULE THE SHORT TERM. ADVISORIES FOR FLOODING HAVE ALL BEEN ALLOWED TO EXPIRE BASED ON REPORTS FROM LAW ENFORCEMENT AND THE LACK OF RAIN OVER THE PAST EIGHT HOURS OR SO IN THOSE ADVISORY AREAS. HYDROLOGIC OUTLOOKS HAVE BEEN ISSUED FOR THE APPLE CREEK IN BURLEIGH COUNTY...AND THE KNIFE RIVER BASIN...MAINLY THROUGH MERCER COUNTY. APPLE CREEK WAS PERFORMING WELL BELOW EXPECTATIONS WHILE THE KNIFE LOOKS LIKE IT WILL APPROACH MINOR FLOOD STAGE BUT MAY NOT MAKE IT TO THAT DEFINED FLOOD LEVEL. WILL BE REMOVING A FEW WESTERN COUNTIES FROM THE FLOOD WARNING IN THE CENTRAL PART OF WESTERN NORTH DAKOTA...AND LIKELY EXTENDING IN TIME THROUGH SUNDAY THE EASTERN PART OF THAT WARNING. HIGH RESOLUTION MODELS DEVELOP THUNDERSTORMS IN EASTERN MONTANA AND BRING THEM THROUGH WESTERN AND CENTRAL NORTH DAKOTA THIS AFTERNOON IN RESPONSE TO A MID LEVEL SHORT WAVE APPROACHING...AND THE CUT OFF MID LEVEL COOL POOL OVER SOUTHERN SASKATCHEWAN INCREASING DEEP LAYER SHEAR. INSTABILITY AND CAPE BECOME SUPPORTIVE OF SEVERE WEATHER ESPECIALLY BETWEEN 2 PM CDT AND 7 PM CDT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 420 AM CDT SUN AUG 17 2014 LOW/TROF CONTINUES ITS EASTWARD PROGRESSION INTO MONDAY WITH PRECIP CONTINUING TO TAPER FROM WEST TO EAST IN THE MORNING. IN THE AFTERNOON...SOME RE-DEVELOPMENT MAY OCCUR AS THE AREA REMAINS UNDER CYCLONIC FLOW...THOUGH MOST LOCATIONS SHOULD DRY OUT BY EVENING. A SHORT LIVED DRY PERIOD IS EXPECTED THROUGH THE DAY ON TUESDAY AS A FAST MOVING SHORT WAVE RIDGE MOVES THROUGH THE AREA. UPPER FLOW STARTS TO SHIFT SOUTHWESTERLY TUESDAY EVENING AS RIDGE PUSHES EAST AND TROF OVER THE WESTERN CONUS DEEPENS. CHANCES FOR PRECIPITATION THEN STEADILY INCREASE THROUGH MID-WEEK AS A VARIETY OF WAVES MOVE THROUGH THE FLOW...WITH THE GREATEST CHANCES COMING LATE WEDNESDAY AS A SFC LOW/BOUNDARY SHIFTS THROUGH THE AREA. MODELS THEN HAVING TROUBLE WITH THE TIMING OF INDIVIDUAL SYSTEMS FOR THE END OF THE WEEK...BUT GENERAL CONSENSUS IS AN ACTIVE PATTERN SO WILL KEEP POPS IN THE FORECAST. NEAR AVERAGE TEMPS EXPECTED THROUGH MID-WEEK WITH MODELS ADVERTISING A COOLING TREND FOR THE END OF THE WEEK/WEEKEND. WILL HAVE TO KEEP AN EYE ON THIS TO SEE HOW SIGNIFICANT OF A COOL DOWN THIS WILL BE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 1012 AM CDT SUN AUG 17 2014 MORNING FOG AND STRATUS WILL CONTINUE TO BURN OFF AND LIFT ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THEREAFTER...A LINE OF POSSIBLY SEVERE THUNDERSTORMS IS FORECAST TO DEVELOP ACROSS WESTERN NORTH DAKOTA AROUND 20 UTC...AND MOVE EAST THROUGH THE EVENING. SEE TAFS FOR EXPECTED TIMING AND IMPACTS TO EACH TERMINAL. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...JPM LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1006 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1006 AM CDT SUN AUG 17 2014 SHOWERS CONTINUE TO DEVELOP OVER THE RED RIVER VALLEY AS THE WEAK UPPER LOW CONTINUES ON ONLY SLOWLY PULL EASTWARD. THESE SHOWERS SHOULD CONTINUE INTO OUR MN COUNTIES FOR THE REST OF THE MORNING AND SHOULD BE OUT OF THE CWA BY LATER IN THE AFTERNOON. THE MAIN UPPER TROUGH CONTINUES TO MOVE SLOWLY THROUGH THE NORTHERN ROCKIES...AND MODELS CONTINUE TO BE PRETTY BULLISH ON BREAKING OUT PRECIP AS THE TROUGH COMES THROUGH. THERE HAS BEEN A FASTER TREND...WITH THE RAP BRINGING THE PRECIP INTO THE RED RIVER VALLEY BY THIS EVENING AND LEAVING THE WESTERN COUNTIES DRY. THE WRF AND NAM ARE NOT QUITE AS FAST...AND GIVEN THE FAIRLY SLOW PROGRESSION OF THE TROUGH AND THE FACT THAT CONVECTION HAS NOT DEVELOPED YET...WILL LEAN TOWARDS THE NAM. SPED UP POPS A BIT THROUGH THIS AFTERNOON AND TONIGHT...BUT CONTINUED THE TREND OF KEEPING US FAIRLY WET THROUGH THE NIGHT. UPDATE ISSUED AT 710 AM CDT SUN AUG 17 2014 WATER VAPOR SHOWS THE 500 MB LOW/VORT HAS INCHED EAST AND WAS IN THE WHEATON MN AREA. GOT CLUSTERS OF SHOWERS AND A FEW STORMS NORTH AND EAST-SOUTHEAST OF SYSTEM OVER WEST CENTRAL-CENTRAL MN THEN BACK INTO SOUTHEASTERN ND. EXPECT ONLY SLOW MOVEMENT OF ENTIRE SYSTEM EAST TODAY. DID UPDATE WESTERN EDGE OF POPS TO INCREASE A BIT IN FARGO-LISBON AREA. ISOLATED SHOWERS IN THE NRN RRV. OTHERWISE 06Z MODEL RUNS SHOW MAIN ACTION MID AFTN IN WRN- CNTRL ND AS A BROKEN LINE OF STORMS FORMS ESTEVAN SK TO WEST OF BISMARCK AND STARTS TO MOVE EAST. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 350 AM CDT SUN AUG 17 2014 UPPER LEVEL LOW/VORT SEEN VERY SLOWLY DRIFTING EAST-NORTHEAST ALONG THE SD/ND BORDER NORTHEAST OF ABERDEEN EARLY THIS MORNING. CONVECTION WTIH THIS FEATURE WANED A BIT SINCE MIDNIGHT AS CLOUD TOPS WARMED WITH SOME NEW CONVECTION FIRING A BIT SOUTH BUT RADAR HAS SHOWN SOME NEW CONVECTION LAST 30 MIN IN FORMAN ND AREA. OVERALL EXPECT THIS SYSTEM TO SLOWLY MOVE EAST-NORTHEAST TODAY WITH MAIN POPS HOLDING IN REGION FROM BEMIDJI-ADA-FARGO-LISBON AREA SOUTHWARD. DID HOWEVER SPREAD SOME LOWER POPS NORTH AS A FEW VERY LIGHT SHOWERS HAVE BEEN ON RADAR DRIFTING EAST BTWN GFK-DVL UP TOWARD WEST OF LANGDON. SHORT RANGE MODELS NOT DOING TOO WELL WITH PRECIP CURRENTLY THRU TODAY. MOST DRIFT MAIN RAIN A BIT TOO FAR NORTH TODAY I BELIEVE. PWATS ARE HIGHEST EARLY ON TODAY BUT DO SLOWLY DECREASE A LITTLE AS DAY PROGRESSES AND SYSTEM SLOWLY MOVES EAST. OUTSIDE OF THIS SYSTEM LOOKS QUIET OVER WRN FCST BALANCE OF TODAY. NEXT SHORT WAVE TROUGH ENTERING WRN ND THIS AFTN AND TSTMS WILL FORM AND SPC HAS A SLIGHT RISK OF SVR WEST OF FCST AREA WITH MU CAPES IN THE 2-3K J/KG RANGE. SHORT WAVE TROUGH DOES MOVE EAST AND INTO THE RRV TOWARD 12Z MON AND THEN EAST THRU NW MINNESOTA MONDAY. KEPT IDEA OF LIKELY POPS SPREADING INTO ERN ND MOSTLY MID EVENIGN SPREADING INTO MN FCST AREA MONDAY. HPC QPF VALUES HAVE DROPPED WITH HPC FCSTS OF A GENERAL HALF INCH TO THREE QUARTERS OF AN INCH. FOR TEMPS...WITH CLOUDS HOLDING IN MOST AREAS TODAY NOT EXPECTING A HUGE RISE WITH MOSTLY 70S THOUGH IF ENOUGH SUN AROUND 80 PSBL IN THE WEST. 70S AGAIN MONDAY WITH CLOUDS. WITH CLOUDS HOLDING...FOG LOOKS A BIT LESS CERTAIN AND THUS SCALED BACK A BIT. NARROW CLEARING ZONE MORE IN ERN WFO BIS FCST AREA. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 350 AM CDT SUN AUG 17 2014 500 MB TROUGH WILL EXIT ERN MN MONDAY NIGHT WITH SHOWER THREAT ENDING. THEN HIGH PRESSURE BUILDS IN TUESDAY. TEMPS HOLDING NR NORMAL. WEDNESDAY-SATURDAY...DURING THIS TIME PERIOD THE SYNOPTIC FLOW PATTERN WILL BE IN TRANSITION TO A WESTERN US TROUGH AND DOWNSTREAM RIDGE...ALTHOUGH VARIOUS MODEL RUNS HAVE SHOWN DIFFERENCES IN THE ORIENTATION OF THIS PATTERN. EITHER WAY...INITIALLY QUIET WEATHER IS EXPECTED TO TREND MORE UNSETTLED LATER IN THE WEEK AS THE UPPER FLOW BECOMES MORE WESTERLY OR SOUTHWESTERLY OVER THE AREA. THERE IS STILL RATHER LOW CONFIDENCE ON THE TIMING OF INDIVIDUAL DISTURBANCES...AND THUS WHEN RAIN CHANCES WILL BE GREATEST. TEMPS WILL CONTINUE TO RUN WITHIN SEVERAL DEGREES OF AVERAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 710 AM CDT SUN AUG 17 2014 TRUE TO FORM RIGHT BEFORE 12Z CIGS CRASHED IN MANY SPOTS TO LOW END MVFR LEVELS AT FAR-BJI-GFK AREA. A BIT HIGHER CIGS DVL-TVF. OVERALL EXPECT MVFR CIGS PREDOMINATE THIS MORNING...TRYING TO LIFT INTO A LOW END VFR CIG THIS AFTN. SHOWERS AND A FEW STORMS THIS MORNING FAR-BJI REGION. TIMING OF NEXT WAVE OF STORMS TONIGHT IS A CHALLENGE...BUT MOST MODELS INDICATE BY 01Z DVL AND BY 05Z GFK- FAR AND A BIT LATER TOWARD BJI. COVERAGE AND INTENSITY OF RAINFALL AND CIGS HIGHLY QUESTIONABLE AT THIS TIME. A LIGHT SOUTHEAST WIND IN GENERAL TODAY/TONIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...RIDDLE LONG TERM...MAKOWSKI/RIDDLE AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
912 PM EDT MON AUG 18 2014 .SYNOPSIS... LOW PRESSURE OVER SOUTHERN OHIO WILL MOVE EAST TO THE VIRGINIA COAST BY TUESDAY MORNING. A STATIONARY FRONT ACROSS CENTRAL OHIO WILL BE DRAWN SOUTH IN THE WAKE OF THE LOW. ANOTHER LOW WILL MOVE INTO THE WESTERN GREAT LAKES OVERNIGHT AND EXPAND ACROSS THE CENTRAL LAKES TUESDAY BRINGING THE FRONT BACK NORTH INTO THE AREA AS A WARM FRONT. THE LOW WILL REMAIN IN THE AREA THROUGH MID WEEK. && .NEAR TERM /THROUGH TUESDAY/... OVERNIGHT WE ARE EXPECTING DRY CONDITIONS. NOT SURE WHY HRRR KEEPS ON AND OFF LIGHT SHRA/SPRINKLES OVER THE EAST THRUT THE NIGHT. THIS AREA IS WHERE THE MODELS HAVE THE DRIEST AIR SO IT DOES NOT SEEM TO MAKE SENSE...UNLESS ITS TRYING TO INDICATE MID LEVEL ATTEMPTS AT PRECIP/VIRGA. MORE CLOUDS ON THE WAY FROM THE WEST OVERNIGHT ASSOCIATED WITH THE LOW MOVING INTO THE WESTERN LAKES. EXPECTING THOSE AFTER MIDNIGHT IN THE WEST ALONG WITH A SLIGHT CHANCE OF SHOWERS OR A THUNDERSTORM TOWARD DAYBREAK. LOWS SHOULD BE IN THE LOWER 60S WITH A FEW UPPER 50S EAST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... THE SOUTHERN OHIO LOW WILL HAVE REACHED THE VIRGINIA COAST BY MORNING WITH THE NEXT LOW MOVING INTO/ THROUGH THE WESTERN LAKES. THIS LOW WILL DOMINATE THE SHORT TERM PERIOD AS IT ROTATES THROUGH THE GREAT LAKES REGION THROUGH MID WEEK. ALSO THE FRONT TO OUR SOUTH WILL BEGIN MOVING NORTHEAST AS A WARM FRONT AS THE LOW APPROACHES AND BY MORNING IT SHOULD EXTEND FROM NEAR CHICAGO TO CINCINNATI. FOLLOWED THE SREF FOR PRECIP TIMING TUESDAY WHICH BRINGS CHANCE POPS INTO THE WEST DURING THE MORNING...INCREASING TO LIKELY BY MID DAY AS THE REST OF THE AREA INCREASES TO CHANCE POPS. BY EARLY EVENING SPREAD THE LIKELY POPS FURTHER EAST ACROSS THE CENTRAL COUNTIES...EVENTUALLY EXPANDING ACROSS THE REMAINDER OF THE EAST LATE EVENING TO OVERNIGHT. WEDNESDAY MORNING THE UPPER LOW WILL REMAIN STUCK OVER NRN MI WITH CONTINUED DIVERGENCE ACROSS NRN OHIO/NWRN PA. AXIS OF DEEPEST MOISTURE WILL BE NEGATIVELY TILTED FROM THE WESTERN LAKES TO PA AND NY. WILL KEEP HIGHEST POPS ACROSS NERN OHIO AND NWRN PA WITH DECREASING CHANCES WEST. THE LOW WILL WEAKEN AND MOVE TO PA/NY THURSDAY AS AN UPPER RIDGE AXIS BUILDS INTO THE UPPER MIDWEST. STILL WILL LIKELY SEE SHOWERS AND THUNDERSTORMS DURING THE DAY GIVEN THE CONTINUED MOISTURE AND DAYTIME HEATING SO WILL CONTINUE WITH CHANCE POPS. TEMPS NEAR NORMAL. && .LONG TERM /FRIDAY THROUGH MONDAY/... UPPER LEVEL LOW MOVES OFF THE EAST COAST ON FRIDAY WITH THE UPPER LEVEL RIDGE OVER THE MISSISSIPPI VALLEY SLOWLY EXPANDING EASTWARD OVER THE WEEKEND. FRIDAY LOOKS LIKE A TRANSITION DAY AND COULD BE ACTIVE WITH SHOWERS AND THUNDERSTORMS AS ENERGY RIDES AROUND THE BUILDING RIDGE. BOTH THE ECMWF AND GFS TRY TO BUILD A STRONG RIDGE OVER THE GREAT LAKES THIS WEEKEND AND EXTENDING NORTHEAST INTO QUEBEC. THIS SHOULD LEAD TO DECREASING CHANCES OF SHOWERS AND THUNDERSTORMS BOTH SATURDAY AND SUNDAY AS MID LEVELS WARM AND WARM FRONT SHIFTS NORTH OF THE AREA. MODELS DO INDICATE SOME LINGERING MOISTURE AND SOMEWHAT OF A BOUNDARY IN PLACE THOUGH SO WILL HOLD ONTO LOW CHANCES OF SHOWERS AND THUNDERSTORMS IN ALL BUT THE EAST WHERE A DRIER EASTERLY FLOW ON THE PERIPHERY OF HIGH PRESSURE TO THE EAST SHOULD LIKELY MAINTAIN DRY CONDITIONS. STILL EXPECT A WARMING TREND OVER THE WEEKEND BUT HAVE BACKED OFF A FEW DEGREES FOR NOW WITH UNCERTAINTY IN CLOUD COVER. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THE EVENING HOURS WILL BE QUIET WITH JUST SOME MID LEVEL CLOUDS. STILL EXPECTING MVFR FOG TO DEVELOP AFTER MIDNIGHT WITH IFR CONDITIONS DEVELOPING AT THE INLAND TAF SITES. CIGS WILL GRADUALLY LOWER ON TUESDAY AS A WARM FRONT LIFTS ACROSS THE REGION. THE NEW GUIDANCE COMING IN IS SLOWER BRINGING PRECIP IN. BEST GUESS RIGHT NOW IS THAT IT WILL BE LATE AFTERNOON BEFORE SCATTERED STORMS BEGIN TO DEVELOP ACROSS THE AREA. GREATEST COVERAGE SHOULD BE OVER NW OHIO...AT LEAST INITIALLY. THE FLOW WILL BECOME LIGHT AND VARIABLE AFTER DARK AND THEN SOUTHERLY ON TUESDAY AS THE FRONT LIFTS. OUTLOOK...NON VFR POSSIBLE IN SHOWERS/THUNDERSTORMS TUESDAY NIGHT THROUGH FRIDAY. && .MARINE... LAKE ERIE IS LOCATED BETWEEN HIGH PRESSURE TO THE NORTH AND A WEAK AREA OF LOW PRESSURE OVER THE OHIO VALLEY. NORTHEAST TO EAST WINDS HAVE INCREASED TO AROUND 15 KNOTS OR SO ALONG MUCH OF THE SOUTH SHORE OF THE LAKE...WITH WAVES OF 1 TO 3 FEET. THE HIGH WILL BUILD TO THE EAST OVERNIGHT AND WINDS WILL DECREASE AS THE GRADIENT RELAXES...SHIFTING TO EASTERLY AND THEN SOUTHEAST LATE. AN AREA OF LOW PRESSURE WILL MOVE INTO THE WESTERN GREAT LAKES ON TUESDAY THEN MOVE ACROSS LAKE ERIE ON WEDNESDAY BRINGING UNSETTLED WEATHER. WINDS WILL GENERALLY REMAIN 15 KNOTS OR LESS AS THEY SHIFT AROUND TO THE WEST BEHIND THIS SYSTEM. HIGH PRESSURE WILL RETURN ON THURSDAY FOLLOWED BY A SLOW MOVING WARM FRONT THAT WILL LIFT NORTH ACROSS THE LAKE OVER THE WEEKEND. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK/ADAMS SHORT TERM...TK LONG TERM...KEC AVIATION...KUBINA MARINE...KEC
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
414 PM EDT SUN AUG 17 2014 .SYNOPSIS... A WEAK LOW PRESSURE SYSTEM OVER SOUTHERN INDIANA WILL BEGIN TO ACCELERATE A LITTLE AS IT CONTINUES TO WEAKEN FURTHER WHILE MOVING ALONG AND JUST SOUTH OF THE OHIO RIVER. SHOWERS AND THUNDERSTORMS WILL GENERALLY STAY FOCUSED SOUTH OF THE OHIO RIVER TONIGHT AND MONDAY NEAR THE PATH OF THE LOW...THOUGH SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE OVER CENTRAL AND SOUTHERN OHIO AND INDIANA AS WELL IN THE VERY HUMID AND MODERATELY UNSTABLE AIRMASS. A BRIEF PERIOD DRY WEATHER IS EXPECTED MONDAY NIGHT INTO EARLY TUESDAY BEFORE THE NEXT WEAK COLD FRONT APPROACHES THE REGION WITH A THREAT FOR SHOWERS AND THUNDERSTORMS. THIS FRONT WILL WASH OUT AND STALL OVER THE AREA...WITH A WARM AND VERY HUMID AIRMASS TAKING HOLD FOR THE LAST HALF OF THE WEEK INTO EARLY NEXT WEEKEND...WITH HIGHS WELL INTO THE 80S AND MILD NIGHTS IN THE 60S AND LOWER 70S. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THIS AFTERNOON OBJECTIVE RAP ANALYSIS AND OBSERVATIONAL DATA SETS /SATELLITE AND RADAR LOOPS/ CONFIRM THE WEAKENING MID LEVEL CLOSED LOW NEARLY STATIONARY OVER SOUTHWESTERN INDIANA. A WEAK COLD FRONT HAD ALSO STALLED ACROSS NORTHERN OHIO. RADAR TRENDS OVER THE LAST FEW HOURS SHOW THAT THE BULK OF STRONG FORCING/DEEPER MOISTURE RESIDED ON THE SRN/SERN FLANK OF THE UPPER LOW...WITH WIDESPREAD SHOWERS AND THUNDERSTORMS OVER KY/TN. THE NERN FLANK OF A SHIELD OF LGT/MOD SHOWERS/RAIN HAS STUBBORNLY BEEN ERODED AS IT MAKES INROADS INTO THE WFO ILN FORECAST AREA. SCT SHRA/TSRA WERE SLOWLY DEVELOPING ALONG THE STALLED FRONT OVER NORTHERN OHIO. MESOANALYSIS LATE THIS AFTERNOON INDICATED A PLUME OF HIGH PWAT REMAINED ATTENDANT TO THE UPPER LOW...WITH PWAT ABOUT 160% OF NORMAL OVER SRN IND/NRN KY NEAR AND JUST EAST OF THE CENTER OF CIRCULATION. A LARGE RESERVOIR OF MID 60S TO MID 70S SURFACE DEWPOINTS EXISTED NEAR THE CIRCULATION AND ESPECIALLY TO THE SOUTH/WEST. INSTBY WAS RATHER MEAGER OWING TO MOIST LAPSE RATES AND AMPLE/WIDESPREAD CLOUDS OVER MUCH OF THE AREA...KEEPING TEMPERATURES IN THE 70S FOR THE MOST PART. ALSO OF IMPORTANCE TO THE SHORT TERM FORECAST IS A STRONG SHORTWAVE TROUGH ACROSS SASK MOVING EAST. TONIGHT...THERE IS STRONG AGREEMENT AMONG 17.12Z DATA THAT THE WEAKENING CLOSED LOW WILL CONTINUE TO SLOWLY WEAKEN AND BECOME A LITTLE MORE PROGRESSIVE AS IT OPENS UP AND SHEARS DOWNSTREAM A BIT. THIS IS OWING TO THE KICKER ENERGY MOVING QUICKLY ACROSS SASK ATOP THE SUBTROPICAL SWRN CONUS RIDGING. SPECIFICALLY...THE 700MB CLOSED LOW WILL PLOD SLOWLY ALONG AND JUST SOUTH OF THE OHIO RIVER THROUGH NORTHERN KENTUCKY REACHING THE CVG AREA BY SUNRISE MONDAY MORNING. GIVEN THE BULK OF THE FLOW/FORCING WILL BE ON THE SOUTH/SOUTHEAST SIDE OF THE CIRCULATION...EXPECT THE MOST WIDESPREAD/HEAVIEST RAIN JUST SOUTH OF THE LOCAL FORECAST AREA. HOWEVER...WILL NEED TO WATCH ANY ACTIVITY THAT FORMS ACROSS NRN KY AS MID LVL STEERING FLOW WILL BE LIGHT NEAR THE PATH OF THE MID LEVEL SYSTEM AND IF A DEFORMATION TYPE RAIN BAND FORMS ACRS OUR NRN KY COUNTIES THE PWAT/WARM RAIN PROCESSES COULD LEAD TO NARROW BAND OF HEAVIER RAIN...BUT RIGHT NOW IT SEEMS THE WEAKENING NATURE OF THE OPENING WAVE AND THE IDEA IT BECOMES MORE PROGRESSIVE WITH TIME SHOULD MITIGATE THIS POTENTIAL A GREAT DEGREE. MAINTAINED THE LIKELY RAIN CHANCES ACROSS OUR FAR SOUTH NEAR THE NOSE OF MODEST NORTHEAST-ORIENTED LOW LEVEL JET THAT POINTS INTO OUR AREA THIS EVENING INTO THE FIRST PART OF THE OVERNIGHT...ALTHOUGH RECENT EXPERIMENTAL /ESRL/ AND PARALLEL /NCEP/ HRRR RUNS ARE NOT VERY BULLISH ON RAIN COVERAGE ACRS NRN KY TONIGHT. ELSEWHERE...AS THERE HAS BEEN DURING THE DAY...SCT SHRA ON THE PERIPHERY OF THE UPPER LOW WILL CON/T TO BE POSSIBLE...WITH ACTIVITY REMAINING LIGHT AND LIKELY NOT CONTAINING THUNDER. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... THROUGH THE DAY MONDAY THE UPPER LEVEL WAVE REALLY OPENS UP/SHEARS OUT/WEAKENS AS DEEPER LAYER NWLY FLOW DRIVING THE KICKER ENERGY TO OUR NW SPREADS ACROSS THE GREAT LAKES. A SURFACE TROUGH/INVERTED TROUGH HANGS BACK OVER THE FORECAST AREA IN THE WAKE OF THE WEAKENING SURFACE LOW...AS DOES THE WEAK/WASHING OUT STATIONARY FRONT OVER NORTHERN OHIO. A VERY MOIST AND UNCAPPED AIRMASS REMAINS DURING PEAK HEATING WITH WIDESPREAD CUMULUS EVENTUALLY CONVECTING DURING DAYTIME HEATING WITH THE SUBTLE SURFACE FORCING MECHANISMS...AND MLCAPE PER 17.12Z FORECAST SOUNDINGS /GFS AND NAM/ OF 1000-1500 J/KG. FLOW IS WEAK SO JUST SOME SLOW MOVING HEAVY RAINERS ALL THAT IS EXPECTED DURING THE AFTERNOON/EARLY EVENING. GIVEN THE AMPLE MOISTURE...AND NOTING THIS REGION WEST OF THE UPPER LOW FAILED TO WARM MUCH TODAY...AM KEEPING HIGHS MOSTLY IN THE 70S TO AROUND 80 ON MONDAY...ON THE COOLER SIDE OF 17.12Z MOS. ON TUESDAY...THE AFOREMENTIONED SHORTWAVE OVER SASK WILL BE ARRIVING WITH A COLD FRONT AT PEAK HEATING WILL ACTUALLY ENCOUNTER A SOMEWHAT FAVORABLE AIRMASS FOR ROBUST CONVECTION. BOUNDARY LAYER FLOW WILL HAVE TURNED TO THE SOUTHWEST WHILE MID LEVEL WNWLY FLOW WILL BE INCREASING AS RIDGING BEGINS TO BUILD A MODEST HEIGHT GRADIENT TO OUR WEST/SOUTH. 17.12Z NAM/GFS FORECAST BUFR SOUNDINGS FOR ILN/CVG/DAY/CMH ALL EXHIBIT MLCAPE FROM 1500 TO 2000 J/KG WITH A STEEPER MID LEVEL LAPSE RATE WITH BOUNDARY LAYER DWPTS STILL IN THE 60S. 0-6KM BULK SHEAR VALUES AROUND 30-35KTS COULD PROMOTE A LITTLE MORE ORGANIZATION TO THE STORMS COMPARED TO MONDAY. UPCOMING SHIFTS MAY NEED TO MOVE TO HIGHER RAIN CHANCES IF CURRENT SIGNALS PERSIST..ESPECIALLY LATER IN THE DAY TUES INTO TUESDAY EVENING. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... UPPER LEVEL RIDGE OVER THE GULF COAST REGION WILL BUILD SLOWLY NORTH INTO THE MID MISSISSIPPI VALLEY THROUGH THE END OF THE WEEK. THIS WILL RESULT IN A NORTHWEST FLOW PATTERN ALOFT THROUGH AT LEAST FRIDAY. BOTH THE 12Z GFS AND 12Z ECMWF CONTINUE TO INDICATE THE POSSIBILITY OF SEVERAL SHORT WAVES RIDING DOWN THROUGH THE AREA IN THIS PATTERN. WITH DEWPOINTS PUSHING UP INTO THE UPPER 60S TO LOWER 70S...THERE SHOULD BE SUFFICIENT INSTABILITY TO CREATE THE POTENTIAL FOR A RATHER ACTIVE PATTERN THROUGH THE END OF THE WEEK. TIMING REMAINS DIFFICULT THOUGH SO WILL KEEP POPS IN THE CHANCE CATEGORY. TEMPERATURES ALSO REMAIN SOMEWHAT PROBLEMATIC AS WE WILL REMAIN IN THE TRANSITION ZONE BETWEEN WARMER TEMPERATURES TO OUR SOUTHWEST/COOLER TO THE NORTHEAST. WILL CONTINUE WITH FAIRLY SEASONABLE HIGHS...BUT OVERNIGHT LOWS MAY REMAIN A LITTLE ON THE WARM SIDE...UPPER 60S TO NEAR 70...GIVEN THE HIGHER DEWPOINTS. SOME UNCERTAINTY EXIST BETWEEN THE 12Z GFS AND 12Z ECMWF OVER THE WEEKEND AS THE GFS IS TRYING TO BUILD THE UPPER LEVEL RIDGE MORE EAST TOWARD OUR AREA...WHILE THE ECMWF BEGINS TO FLATTEN OUT THE RIDGE AS SHORT WAVE ENERGY MOVES ACROSS THE UPPER GREAT LAKES. HAVE TRENDED MORE TOWARD THE GFS...DECREASING POPS THROUGH THE WEEKEND AND ALLOWING FOR A CONTINUED SLOW WARMUP IN TEMPS THROUGH SUNDAY. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... LOW PRESSURE TRAVELING THROUGH KENTUCKY WILL HAVE VARYING EFFECTS ON TAF SITES. SOUTHERN SITES CVG AND LUK WILL HAVE SHOWERS IN THE VICINITY THROUGH MUCH OF THE PERIOD AS THE LOW SPINS NEARBY TO THE SOUTH. CEILINGS BELOW 2000 FT WILL BE POSSIBLE THERE LATE TONIGHT IN A MOIST BOUNDARY LAYER...AND BR AND HZ WILL REDUCE VISIBILITIES TONIGHT INTO MONDAY. CONDITIONS COULD IMPROVE MONDAY AFTERNOON AS THE LOW MOVES EAST. FARTHER NORTH AT ILN DAY CMH AND LCK...THE SYSTEM IS FORECAST TO PRODUCE MUCH LESS PRECIPITATION. WENT WITH VCSH THIS AFTERNOON INTO THIS EVENING...WITH NO PRECIP IN THE FORECAST THEREAFTER. CEILINGS MAY FALL INTO THE MVFR RANGE AT DAY AND ILN WHILE REMAINING VFR AT CMH AND LCK. BR WILL BE POSSIBLE AT DAY ILN AND LCK...WITH THE TYPICALLY WARMER CMH REMAINING FREE FROM SURFACE OBSCURATION. WIND DIRECTION WILL VARY WITH RESPECT TO THE POSITION OF THE LOW AND A WEAK FRONT THAT IS WASHING OUT OVER CENTRAL OHIO. WIND SPEEDS ARE EXPECTED TO REMAIN BELOW 10 KNOTS. OUTLOOK...THUNDERSTORMS POSSIBLE TUESDAY THROUGH THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...JGL AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
125 PM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT OVER LAKE ERIE WILL SLOWLY MOVE SOUTH ACROSS THE AREA TODAY. THE WILL STALL IN CENTRAL OHIO TONIGHT. LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT ON MONDAY. ANOTHER WEAK LOW PRESSURE AREA WILL MOVE FORM THE UPPER MIDWEST ACROSS THE AREA LATE TUESDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED...CLOUD COVER ASSOCIATED WITH THE FRONT ACROSS THE AREA IS NOT GOING ANYWHERE FAST ALTHOUGH DURING THE AFTERNOON WE SHOULD LIKELY GET SOME BREAKUP AND SPORADIC THINNING. HRRR CONTINUES TO SUPPORT NO BIG INCREASE IN PRECIP ACROSS THE AREA THROUGH THE AFTERNOON SO WILL CONTINUE WITH THE LOW CHANCE POPS CENTRAL AND SOUTH AND HAVE ALSO TRIMMED NORTHERN EXTENT OF THUNDER. TRIMMED TEMPS AGAIN ESP NORTHWEST. ORIGINAL... THE WEAK COLD FRONT WILL SLIDE ACROSS THE NORTHERN COUNTIES NEAR LAKE ERIE THIS MORNING. THERE IS STILL SOME QUESTION AS TO HOW FAR AND HOW FAST THE COLD FRONT WILL MOVE SOUTH TODAY. I SUSPECT IT MAY NOT MATTER MUCH SINCE THE FRONT IS SHALLOW AND LOW AND MID LEVEL INSTABILITY MAY LINGER NORTH OF THE FRONT SO SHOWERS MAY CONTINUE TO DEVELOP. WILL KEEP A CHANCE OF SHOWERS OR A THUNDERSTORMS EVERYWHERE EXCEPT NORTH OF THE TURNPIKE BY THIS AFTERNOON. SOME CLEARING IS LIKELY ACROSS NORTHEAST OH AND NORTHWEST PA. COOLER AIR WILL BEGIN TO SPILL ACROSS LAKE ERIE AND IT MAY NOT MAKE IT ABOVE THE LOWER 70S ALONG THE LAKESHORE ESPECIALLY AROUND ASHTABULA AND ERIE. GENERALLY 75 TO 80 ELSEWHERE...LOWER 80S IN THE FAR SOUTH FROM FINDLAY TO MARION AND MOUNT VERNON WHERE IT WILL ALSO BE RELATIVELY HUMID WITH DEWPOINTS HOLDING IN THE MID TO UPPER 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE FRONT SHOULD PUSH SOUTH OF THE AREA TONIGHT. CANNOT RULE OUT A SHOWER ACROSS THE SOUTHERN COUNTIES SOUTH OF ROUTE 30 OTHERWISE DRY. WITH LOWERING DEWPOINTS AND THE WIND BECOMING LIGHT...THE COOL SPOTS OF EXTREME NE OH/NW PA COULD DROP TO THE LOWER 50S OR PERHAPS UPPER 40S TONIGHT OTHERWISE LOWS MOSTLY IN THE UPPER 50S TO LOWER 60S. THE SURFACE LOW SHOULD MOVE EAST ALONG THE STALLED FRONT ON MONDAY. THE MAJORITY OF RAIN SHOULD STAY SOUTH OF THE FORECAST AREA. WITH THE STALLED FRONT JUST TO OUR SOUTH THOUGH...SOME OVER RUNNING SHOWERS AND PERHAPS A RUMBLE OF THUNDER IS PROBABLE....AGAIN MAINLY FROM AROUND THE TURNPIKE SOUTH. HIGHS MOSTLY IN THE MID AND UPPER 70S. THE NEXT SHORT WAVE AND WEAK COLD FRONT WILL APPROACH ON TUESDAY. THE SHOWERS MAY SPREAD IN QUICKLY BUT I PREFER THE SLOWER SOLUTIONS BASED ON THE RELATIVELY SLOW MOVEMENT PROGGED OF THE SHORT WAVE. THIS SHOULD ALLOW FOR A LITTLE SUNSHINE AND THE CHANCE TO BUBBLE UP SOME DECENT SHOWERS AND THUNDERSTORMS. HIGHS GENERALLY NEAR 80 OR THE LOWER 80S WITH DEWPOINTS IN THE MID AND UPPER 60S... ALMOST LIKE SUMMER TIME. SHOWERS WILL PROBABLY REDEVELOP ON WEDNESDAY...ESPECIALLY ACROSS NE OH/NW PA...AS THE SLOW MOVING SHORT WAVE CROSSES THE AREA. HIGHS SHOULD GET INTO THE 80S EXCEPT WHERE THERE ARE MORE NUMEROUS SHOWERS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE LONG TERM STARTS OFF WITH A CLOSED LOW OVER THE LOWER GREAT LAKES. H850 FLOW SHOULD BRING HIGH PWATS AND MOIST IN WITH THE GFS SHOWING ANOMALOUS PWATS THU INTO FRI. THE LARGER SCALE MODELS SHOW THE BEST MOISTURE CORRESPONDS TO WEAK JET DYNAMICS AND MODERATE INSTABILITIES. THEREFORE HAVE KEPT POPS AROUND 30-40 PRIMARILY DURING PEAK HEATING...THOUGH ELEVATED CONVECTION POSSIBLE UNTIL THE UPPER LOW SKIRTS TO OUR EAST AND CUTS OFF THE BEST MOISTURE ON SATURDAY. FOR NEXT WEEKEND THE ECMWF/GFS DIFFER NOTABLY ON THE BREAK DOWN (OR NOT) OF THE UPPER LOW OVER THE GREAT LAKES. THE ECMWF MOVES THE LOW OVER NEW ENGLAND WITH A SFC LOW DEVELOPING OFF THE MID ATLANTIC. THE GFS HOWEVER SHOWS THE LOW MOVING OFF THE ATLANTIC COAST RESULTING IN A LESS AMPLIFIED FLOW ALOFT OVER THE GREAT LAKES. THIS CAUSES UNCERTAINLY LATE IN THE FCST WHERE TEMPERATURES COULD BE IN THE UPPER 70S OR THE UPPER 80S DEPENDING ON WHICH SCENARIO PLAYS OUT. BOTH SCENARIOS DO SUGGEST A CUT OFF OF MOISTURE WHICH WOULD REDUCE RAIN CHANCES. WILL CONTINUE WITH FORECAST TREND OF LOW 80S AND A NON-GFS SOLUTION FOLLOWING HPC`S LEAD. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... RESIDUAL BOUNDARY POSITIONED FROM NEAR KTOL TO NEAR KMFD AND IS EXPECTED TO MOVE LITTLE DURING THE PERIOD. FRONT DIVIDES UPPER 60S DEWPOINTS FROM UPPER 50 DEWPOINTS. HIGH PRESSURE TO THE NORTH DRAWING IN DRIER AIR INTO FAR NE OH/NW PA...WHICH HAS ERODED MOST OF THE NON-VFR CEILINGS FROM EARLIER TODAY. FRONT MAY SPARK A FEW SHOWERS DURING PEAK HEATING...BUT LOW COVERAGE. WITH ALL OF THE LINGERING LOW LEVEL MOISTURE EXPECTING RESTRICTIONS TO VISIBILITY OVERNIGHT/EARLY MONDAY MORNING...ESPECIALLY FOR FDY/MFD WHERE SOME IFR VSBY/CIGS COULD DEVELOP. IMPROVING CONDITIONS MONDAY. OUTLOOK...NON VFR POSSIBLE IN SHOWERS/THUNDERSTORMS TUESDAY THROUGH FRIDAY. && .MARINE... WITH A COLD FRONT MOVING SOUTH ACROSS THE LAKE THIS MORNING WINDS WILL SWITCH TO THE NORTH AND NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH THROUGH EARLY NEXT WEEK KEEPING WINDS 15KT OR LESS. THE NE FLOW THROUGH TUESDAY WILL KEEP A CHOP ESPECIALLY ALONG THE WESTERN BASIN...WITH WAVE HEIGHTS 3 FT OR LESS. A WARM FRONT WILL LIFT NORTH TUESDAY NIGHT AND A WEAK DISTURBANCE WILL MOVE ACROSS THE LAKES. WINDS AND WAVES EXPECTED TO REMAIN BELOW SCA THROUGHOUT. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KOSARIK NEAR TERM...TK/KOSARIK SHORT TERM...KOSARIK LONG TERM...JAMISON AVIATION...JAMISON MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1140 AM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT OVER LAKE ERIE WILL SLOWLY MOVE SOUTH ACROSS THE AREA TODAY. THE WILL STALL IN CENTRAL OHIO TONIGHT. LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT ON MONDAY. ANOTHER WEAK LOW PRESSURE AREA WILL MOVE FORM THE UPPER MIDWEST ACROSS THE AREA LATE TUESDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED...CLOUD COVER ASSOCIATED WITH THE FRONT ACROSS THE AREA IS NOT GOING ANYWHERE FAST ALTHOUGH DURING THE AFTERNOON WE SHOULD LIKELY GET SOME BREAKUP AND SPORADIC THINNING. HRRR CONTINUES TO SUPPORT NO BIG INCREASE IN PRECIP ACROSS THE AREA THROUGH THE AFTERNOON SO WILL CONTINUE WITH THE LOW CHANCE POPS CENTRAL AND SOUTH AND HAVE ALSO TRIMMED NORTHERN EXTENT OF THUNDER. TRIMMED TEMPS AGAIN ESP NORTHWEST. ORIGINAL... THE WEAK COLD FRONT WILL SLIDE ACROSS THE NORTHERN COUNTIES NEAR LAKE ERIE THIS MORNING. THERE IS STILL SOME QUESTION AS TO HOW FAR AND HOW FAST THE COLD FRONT WILL MOVE SOUTH TODAY. I SUSPECT IT MAY NOT MATTER MUCH SINCE THE FRONT IS SHALLOW AND LOW AND MID LEVEL INSTABILITY MAY LINGER NORTH OF THE FRONT SO SHOWERS MAY CONTINUE TO DEVELOP. WILL KEEP A CHANCE OF SHOWERS OR A THUNDERSTORMS EVERYWHERE EXCEPT NORTH OF THE TURNPIKE BY THIS AFTERNOON. SOME CLEARING IS LIKELY ACROSS NORTHEAST OH AND NORTHWEST PA. COOLER AIR WILL BEGIN TO SPILL ACROSS LAKE ERIE AND IT MAY NOT MAKE IT ABOVE THE LOWER 70S ALONG THE LAKESHORE ESPECIALLY AROUND ASHTABULA AND ERIE. GENERALLY 75 TO 80 ELSEWHERE...LOWER 80S IN THE FAR SOUTH FROM FINDLAY TO MARION AND MOUNT VERNON WHERE IT WILL ALSO BE RELATIVELY HUMID WITH DEWPOINTS HOLDING IN THE MID TO UPPER 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE FRONT SHOULD PUSH SOUTH OF THE AREA TONIGHT. CANNOT RULE OUT A SHOWER ACROSS THE SOUTHERN COUNTIES SOUTH OF ROUTE 30 OTHERWISE DRY. WITH LOWERING DEWPOINTS AND THE WIND BECOMING LIGHT...THE COOL SPOTS OF EXTREME NE OH/NW PA COULD DROP TO THE LOWER 50S OR PERHAPS UPPER 40S TONIGHT OTHERWISE LOWS MOSTLY IN THE UPPER 50S TO LOWER 60S. THE SURFACE LOW SHOULD MOVE EAST ALONG THE STALLED FRONT ON MONDAY. THE MAJORITY OF RAIN SHOULD STAY SOUTH OF THE FORECAST AREA. WITH THE STALLED FRONT JUST TO OUR SOUTH THOUGH...SOME OVER RUNNING SHOWERS AND PERHAPS A RUMBLE OF THUNDER IS PROBABLE....AGAIN MAINLY FROM AROUND THE TURNPIKE SOUTH. HIGHS MOSTLY IN THE MID AND UPPER 70S. THE NEXT SHORT WAVE AND WEAK COLD FRONT WILL APPROACH ON TUESDAY. THE SHOWERS MAY SPREAD IN QUICKLY BUT I PREFER THE SLOWER SOLUTIONS BASED ON THE RELATIVELY SLOW MOVEMENT PROGGED OF THE SHORT WAVE. THIS SHOULD ALLOW FOR A LITTLE SUNSHINE AND THE CHANCE TO BUBBLE UP SOME DECENT SHOWERS AND THUNDERSTORMS. HIGHS GENERALLY NEAR 80 OR THE LOWER 80S WITH DEWPOINTS IN THE MID AND UPPER 60S... ALMOST LIKE SUMMER TIME. SHOWERS WILL PROBABLY REDEVELOP ON WEDNESDAY...ESPECIALLY ACROSS NE OH/NW PA...AS THE SLOW MOVING SHORT WAVE CROSSES THE AREA. HIGHS SHOULD GET INTO THE 80S EXCEPT WHERE THERE ARE MORE NUMEROUS SHOWERS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE LONG TERM STARTS OFF WITH A CLOSED LOW OVER THE LOWER GREAT LAKES. H850 FLOW SHOULD BRING HIGH PWATS AND MOIST IN WITH THE GFS SHOWING ANOMALOUS PWATS THU INTO FRI. THE LARGER SCALE MODELS SHOW THE BEST MOISTURE CORRESPONDS TO WEAK JET DYNAMICS AND MODERATE INSTABILITIES. THEREFORE HAVE KEPT POPS AROUND 30-40 PRIMARILY DURING PEAK HEATING...THOUGH ELEVATED CONVECTION POSSIBLE UNTIL THE UPPER LOW SKIRTS TO OUR EAST AND CUTS OFF THE BEST MOISTURE ON SATURDAY. FOR NEXT WEEKEND THE ECMWF/GFS DIFFER NOTABLY ON THE BREAK DOWN (OR NOT) OF THE UPPER LOW OVER THE GREAT LAKES. THE ECMWF MOVES THE LOW OVER NEW ENGLAND WITH A SFC LOW DEVELOPING OFF THE MID ATLANTIC. THE GFS HOWEVER SHOWS THE LOW MOVING OFF THE ATLANTIC COAST RESULTING IN A LESS AMPLIFIED FLOW ALOFT OVER THE GREAT LAKES. THIS CAUSES UNCERTAINLY LATE IN THE FCST WHERE TEMPERATURES COULD BE IN THE UPPER 70S OR THE UPPER 80S DEPENDING ON WHICH SCENARIO PLAYS OUT. BOTH SCENARIOS DO SUGGEST A CUT OFF OF MOISTURE WHICH WOULD REDUCE RAIN CHANCES. WILL CONTINUE WITH FORECAST TREND OF LOW 80S AND A NON-GFS SOLUTION FOLLOWING HPC`S LEAD. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... A COLD FRONT IS CURRENTLY PUSHING SOUTH THROUGH THE REGION BRINGING IFR CEILINGS IN IT`S WAKE. AT THE TIME OF THIS ISSUANCE THE FRONT WAS ALLIGNED FROM TOLEDO TO YOUNGSTOWN AND MOVING SOUTH. DRIER AIR WILL MOVE IN AND ERODE THE CLOUDS STARTING IN ERI AND THEN CLE BY MIDDAY. RAIN CHANCES WILL CONTINUE ALONG THE FRONT THROUGH EARLY AFTERNOON. THE FRONT WILL WASH OUT AND KEEP THE LOW LEVELS MOIST FOR MFD TO FDY SO IFR CONDITIONS WILL BE POSSIBLE EARLY MONDAY. OUTLOOK...NON VFR POSSIBLE OVERNIGHT AND THEN IN SHOWERS/THUNDERSTORMS THROUGH THURSDAY. && .MARINE... WITH A COLD FRONT MOVING SOUTH ACROSS THE LAKE THIS MORNING WINDS WILL SWITCH TO THE NORTH AND NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH THROUGH EARLY NEXT WEEK KEEPING WINDS 15KT OR LESS. THE NE FLOW THROUGH TUESDAY WILL KEEP A CHOP ESPECIALLY ALONG THE WESTERN BASIN...WITH WAVE HEIGHTS 3 FT OR LESS. A WARM FRONT WILL LIFT NORTH TUESDAY NIGHT AND A WEAK DISTURBANCE WILL MOVE ACROSS THE LAKES. WINDS AND WAVES EXPECTED TO REMAIN BELOW SCA THROUGHOUT. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KOSARIK NEAR TERM...TK/KOSARIK SHORT TERM...KOSARIK LONG TERM...JAMISON AVIATION...JAMISON MARINE...JAMISON
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
621 AM EDT SUN AUG 17 2014 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL TRAVERSE THE OHIO VALLEY REGION TODAY INTO TONIGHT. THIS FEATURE WILL MOVE TO THE EAST ON MONDAY WHILE A LINGERING WEAK FRONTAL BOUNDARY REMAINS ACROSS THE REGION. IN A NORTHWEST FLOW ALOFT...A SERIES OF UPPER LEVEL DISTURBANCES WILL THEN ROTATE SOUTHEAST ACROSS THE GREAT LAKES AND OHIO VALLEY THROUGH THE REMAINDER OF THE WEEK...KEEPING THE THREAT OF PRECIPITATION IN THE FORECAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A WEAK COLD FRONT WILL DROP SOUTH INTO THE NRN CWFA TODAY WHILE A COMPACT UPR LVL DISTURBANCE AND WEAK SFC LOW ROTATE SLOWLY EAST/SOUTHEAST TOWARD THE MIDDLE OHIO VALLEY. FOCUS FOR TODAY WILL BE ON THE PROSPECTS FOR SHOWERS AND THUNDERSTORMS. ALTHOUGH PWATS WILL REMAIN HIGH...1.75 TO NEAR 2 INCHES...THERE WILL BE A LACK OF STRONG FORCING OVER MUCH OF THE REGION. THE EXCEPTION WILL BE THE TRI-STATE REGION WHERE THE APPROACH OF AFOREMENTIONED COMPACT DISTURBANCE MAY PUSH A WEAK LOW LEVEL JET TOWARD THIS AREA BY THE AFTERNOON HOURS. HAVE ADJUSTED THE FORECAST TO BRING IN HIGHER POPS TO THIS AREA BASED ON THE LATEST HRRR AND RUC. THE QUESTION WILL STILL BE HOW FAR EAST/NORTHEAST THE LIKELY POPS WILL GET BETWEEN THE AFTERNOON AND EVENING HOURS...AND THAT WILL BE THE AREA TO WATCH FOR ANY ADDITIONAL UPDATES. ELSEWHERE...WEAK FORCING SHOULD KEEP CHANCES FOR SHOWERS/STORMS AROUND 30 TO 40 PERCENT. SKIES WILL BE MOSTLY CLOUDY TO CLOUDY WHICH SHOULD HOLD TEMPERATURES DOWN IN THE UPPER 70S TO THE LOWER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THE 00Z ECMWF AND 00Z GFS HAVE BEEN USED FOR THE SHORT TERM FORECAST. THE 00Z NAM CONTINUES TO SUFFER WITH CONVECTIVE FEEDBACK ISSUES IN WHICH IT GENERATES SMALL BUT YET SUBSTANTIAL LOW LEVEL JETLETS WHICH SEEM UNREALISTIC GIVEN SUCH A WEAK AND SHEARING OUT SYSTEM. AFOREMENTIONED COMPACT UPR LVL DISTURBANCE WILL BEGIN TO SHEAR TONIGHT AS IT TRAVELS MORE EAST NEAR OUR SRN CWFA. BEST LOW LEVEL FORCING AND DYNAMICS WILL REMAIN ALONG AND SOUTH OF THE OHIO RIVER AND THAT IS WHERE LIKELY POPS HAVE BEEN PLACED. CHANCES FOR PCPN WILL DROP OFF CONSIDERABLY HEADING NORTH DUE TO THE LOSS OF INSTABILITY AND FAIRLY WEAK FORCING WITH A NEARLY STATIONARY FRONTAL BOUNDARY. PWATS WILL REMAIN HIGH...ESPECIALLY ALONG AND SOUTH OF THE OHIO RIVER...AND THERE COULD STILL BE SOME LOCALIZED FLOODING WHERE THE HEAVIER SHOWERS/STORMS OCCUR. WILL CONTINUE TO MENTION THIS IN THE HWO. LOWS TONIGHT WILL RANGE FROM THE MID TO THE UPPER 60S. ON MONDAY...DISTURBANCE WILL EXIT OFF TO OUR EAST DURING THE MORNING. AS IT DOES...LIKELY POPS WILL SHIFT OFF TO THE EAST AS WELL. BY THE AFTERNOON...THE WEAK FRONTAL BOUNDARY WILL REMAIN OVER THE REGION. THIS BOUNDARY...ALONG WITH DAYTIME HEATING...WILL PRODUCE SOME SCATTERED CONVECTION...WITH POPS IN THE 30 TO 40 PERCENT RANGE. CLOUDS WILL HOLD TEMPERATURES DOWN ONCE AGAIN WITH UPPER 70S TO LOWER 80S FORECAST. BY MONDAY NIGHT...THE LOSS OF DAYTIME HEATING WILL MEAN A DOWNWARD TREND IN INSTABILITY. AND WITH NO SIGNIFICANT SYSTEMS EXPECTED...WE SHOULD EVENTUALLY DRY OUT WITH THE PCPN THREAT COMING TO AN END DURING THE EVENING OR AROUND MIDNIGHT. LOWS WILL ONCE AGAIN WILL RANGE FROM THE MID TO THE UPPER 60S. FOR TUESDAY INTO TUESDAY NIGHT...UNDER A NORTHWEST FLOW ALOFT...ANOTHER S/WV IS FORECAST TO ROTATE EAST/SOUTHEAST ACROSS THE GREAT LAKES. THE COMBINATION OF THIS FEATURE AND A WEAK REFLECTED SFC TROF AXIS WILL BRING AN INCREASE CHANCE OF SHOWERS AND THUNDERSTORMS...WITH THE BEST CHANCE FROM LATE AFTERNOON INTO THE EVENING HOURS. WE SHOULD BE ABLE TO SEE SOME SUN EARLY ON AND THIS WILL ALLOW TEMPERATURES TO WARM BACK INTO THE LOWER AND MID 80S. LOWS TUESDAY NIGHT WILL FALL BACK INTO THE MID AND UPPER 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... UPPER LEVEL RIDGING WILL BUILD FROM THE GULF COAST UP INTO THE CENTRAL PLAINS THROUGH THE END OF THE WEEK. THIS WILL KEEP THE MID OHIO VALLEY IN NORTHWEST FLOW ALOFT THROUGH MID TO LATE WEEK BEFORE POSSIBLY TRANSITIONING TO MORE OF A NORTHERLY FLOW PATTERN ALOFT HEADING INTO NEXT WEEKEND. A SERIES OF MID LEVEL SHORTWAVES ARE FORECAST TO DROP DOWN THROUGH THE REGION THROUGH MUCH OF THE LONG TERM PERIOD. THIS WILL RESULT IN A CONTINUED CHANCE OF SHOWERS/THUNDERSTORMS THROUGH THE WEEK. HOWEVER...THE MODELS TEND TO STRUGGLE WITH THE TIMING/PLACEMENT OF SHORT WAVES IN THIS KIND OF A PATTERN. WILL THEREFORE GENERALLY JUST KEEP POPS IN THE CHANCE CATEGORY WITH A BIT OF A DIURNAL ENHANCEMENT TO THEM. GIVEN THE NORTHWEST FLOW PATTERN...EXPECT SOMEWHAT OF A NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT ACROSS THE AREA THROUGH THE WEEK BUT OVERALL TEMPERATURES SHOULD BE FAIRLY SEASONABLE. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... AREA OF RAIN WITH SCATTERED EMBEDDED MODERATE SHOWERS LOCATED OVER SOUTH CENTRAL INDIANA AND EXTENDING SOUTHEASTWARD INTO NORTHERN KENTUCKY IS ASSOCIATED WITH ISENTROPIC LIFT. THIS PRECIPITATION IS SLIDING TO THE EAST SOUTHEAST AND IS EXPECTED TO BEGIN WEAKENING AFTER 09Z. HAVE INTRODUCED VCSH INTO THE FIRST PERIOD OF THE KCVG TAF TO REPRESENT THIS FEATURE SINCE THE BULK OF THE PRECIPITATION WILL BE WEST AND SOUTH OF KCVG. CONDITIONS WILL BE SOMEWHAT FAVORABLE FOR THE FORMATION OF MAINLY MVFR FOG TO LOCALLY IFR IN THE FOG PRONE AREAS. THE REASON FOR THE FOG FORMATION IS MAINLY DUE TO THE RESIDUAL MOISTURE FROM EARLIER PRECIPITATION. WINDS TONIGHT WILL BE CALM TO LIGHT SOUTHWESTERLY. AS THE LOW FROM THE WEST APPROACHES THE AREA THE BEST CHANCE FOR PRECIPITATION WILL BE KCVG AND KLUK. THUS VCSH IN THE MORNING BECOMING VCTS IN THE AFTERNOON BECOMING TEMPO TS IN THE EVENING. AS THE FRONT APPROACHES FROM THE NORTH HAVE ADDED VCSH TO THE CENTRAL OHIO TAFS FOR LATE AFTERNOON AND EVENING. IN THE KDAY AND KILN TAFS HAVE REDUCED VCTS TO VCSH AS THEY WILL BE LOCATED BETWEEN THE TWO WEATHER PRODUCING SYSTEMS. WINDS WILL BE OUT OF THE SOUTH AT LESS THAN 10 KTS ON SUNDAY. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY THROUGH THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...HICKMAN SHORT TERM...HICKMAN LONG TERM...HICKMAN AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
152 AM EDT SUN AUG 17 2014 .SYNOPSIS... A SLOW MOVING LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY WILL CONTINUE TO CREEP SLOWLY EASTWARD AS IT SLOWLY WEAKENS. A PLUME OF UNSEASONABLY DEEP MOISTURE AHEAD OF THE SYSTEM WILL CONTINUE TO SPREAD INTO AND THROUGH THE OHIO VALLEY TONIGHT AND SUNDAY...AND THIS MOISTURE AND COMBINED WITH SUBTLE DISTURBANCES AHEAD OF THE LOW WILL CONTINUE TO ALLOW SHOWERS TO DEVELOP AT TIMES TONIGHT THROUGH SUNDAY IN SCATTERED FASHION. THE SLOW MOVING LOW WILL MOVE INTO THE TRI STATE ON SUNDAY NIGHT AND MONDAY...SHIFTING EAST OF THE AREA MONDAY NIGHT. THIS WILL BRING SHOWERS AND A FEW THUNDERSTORMS...PRIMARILY TO AREAS ALONG AND SOUTH OF THE OHIO RIVER...BUT ALL AREAS WILL SEE AT LEAST SOME THREAT OF RAIN WITH THIS SYSTEM. IT WILL BE HUMID AND MILD DESPITE AMPLE CLOUDS SUNDAY AND MONDAY. IN THE WAKE OF THIS SYSTEM ON TUESDAY...AND CONTINUING THROUGH THE REST OF THE WORK WEEK...WILL BE A WARM AND MUGGY AIRMASS WITH DAILY THREATS FOR SHOWERS AND THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATEST RAP MODEL SHOWS EMBEDDED MID LEVEL S/W TRACKING EAST THRU NRN KY. THIS FEATURE...ALONG WITH ISENTROPIC LIFT LEAD TO ISOLD TO SCATTERED SHOWERS LATE THIS AFTN INTO THIS EVENING. WITH THE PASSAGE OF THIS FEATURE...EXPECT A GENERAL LULL IN PRECIPITATION OVERNIGHT. HAVE TRENDED POPS A SLIGHTLY LOWER TONIGHT DUE TO WEAK FORCING WITH A SLIGHT INCREASE (STILL IN CHANCE CATEGORY) INTO THE SW LATE...CLOSER TO MODEST LOW LEVEL JET POINTING INTO SRN IND. GIVEN INCREASE IN MOISTURE...LOWS TONIGHT WILL BE CONSIDERABLY WARMER THAN YDA...WITH LOWS IN THE MID AND UPPER 60S. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/... THE WEAK CLOSED LOW DRIFTING SOUTHEAST THROUGH THE MID MISSISSIPPI VALLEY WILL BEGIN TO WEAKEN FURTHER AND SHEAR EASTWARD MORE QUICKLY BEGINNING SUNDAY INTO SUNDAY NIGHT. THIS PROCESS STILL KEEPS THE BULK OF THE FORCING WEST /ESPECIALLY SOUTHWEST/ OF THE ILN FORECAST AREA ON SUNDAY...WHILE A COLD FRONT THAT HAS DROPPED INTO NRN OHIO ATTENDANT TO ENERGY DIVING THROUGH SERN CANADA COMES TO A HALT. BUT TROPOSPHERIC MOISTURE WILL CONTINUE TO BUILD WITH PWATS EXCEEDING 1.75" ACROSS THE SOUTHERN FORECAST AREA. AREAS OF SHOWERS WILL STILL BE POSSIBLE ACROSS THE AREA IN THE WEAKLY FORCED REGION DOWNSTREAM OF THE WEAK CLOSED LOW...BUT DON/T SEE MORE ORGANIZED ACTIVITY PUSHING INTO THE SOUTHERN/WESTERN AREAS UNTIL EARLY SUNDAY EVENING OR INTO SUNDAY NIGHT. FLOW IS PRETTY WEAK OVERALL SO NOT EXPECTING ANY THREAT OF SEVERE...BUT INDIVIDUAL CORES WILL BE SLOW MOVING AND WITH THE AMPLE MOISTURE THERE COULD BE SOME LOCALIZED HEAVY RAIN LATER SUNDAY NIGHT INTO MONDAY IN OUR SOUTH. THINK OVERALL THIS THREAT IS LOWER THAN WHAT PREVIOUS GUIDANCE HAD INDICATED...AS MODELS HAVE TRENDED FASTER/WEAKER/MORE SHEARED WITH THE CLOSE LOW AS IT SHIFTS ACROSS KENTUCKY AND OPENS UP AND BECOMES MORE PROGRESSIVE. NOTICED WPC STILL KEEPS FAR SOUTHERN AREAS IN SLGT RISK FOR FLASH FLOOD EXCEEDING RAINS...SO WILL KEEP THIS IN THE HAZ WX OUTLOOK BUT REFINE THE THREAT AREA TO CLOSER TO THE TRACK OF MID LEVEL CIRCULATION WHERE POTENTIAL FOR REGENERATION ALONG THE MAJOR AXIS OF SHOWER/STORM POTENTIAL IS GREATEST. AMPLE CLOUDS AGAIN EXPECTED SUNDAY INTO MONDAY SHOULD KEEP HIGHS IN CHECK FOR THE MOST PART...70S TO LOWER 80S...IN WHAT WILL BE QUITE A HUMID AIRMASS. && .LONG TERM /TUESDAY THROUGH SATURDAY/... UPPER LEVEL RIDGING WILL BUILD FROM THE GULF COAST UP INTO THE CENTRAL PLAINS THROUGH THE END OF THE WEEK. THIS WILL KEEP THE MID OHIO VALLEY IN NORTHWEST FLOW ALOFT THROUGH MID TO LATE WEEK BEFORE POSSIBLY TRANSITIONING TO MORE OF A NORTHERLY FLOW PATTERN ALOFT HEADING INTO NEXT WEEKEND. A SERIES OF MID LEVEL SHORTWAVES ARE FORECAST TO DROP DOWN THROUGH THE REGION THROUGH MUCH OF THE LONG TERM PERIOD. THIS WILL RESULT IN A CONTINUED CHANCE OF SHOWERS/THUNDERSTORMS THROUGH THE WEEK. HOWEVER...THE MODELS TEND TO STRUGGLE WITH THE TIMING/PLACEMENT OF SHORT WAVES IN THIS KIND OF A PATTERN. WILL THEREFORE GENERALLY JUST KEEP POPS IN THE CHANCE CATEGORY WITH A BIT OF A DIURNAL ENHANCEMENT TO THEM. GIVEN THE NORTHWEST FLOW PATTERN...EXPECT SOMEWHAT OF A NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT ACROSS THE AREA THROUGH THE WEEK BUT OVERALL TEMPERATURES SHOULD BE FAIRLY SEASONABLE. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AREA OF RAIN WITH SCATTERED EMBEDDED MODERATE SHOWERS LOCATED OVER SOUTH CENTRAL INDIANA AND EXTENDING SOUTHEASTWARD INTO NORTHERN KENTUCKY IS ASSOCIATED WITH ISENTROPIC LIFT. THIS PRECIPITATION IS SLIDING TO THE EAST SOUTHEAST AND IS EXPECTED TO BEGIN WEAKENING AFTER 09Z. HAVE INTRODUCED VCSH INTO THE FIRST PERIOD OF THE KCVG TAF TO REPRESENT THIS FEATURE SINCE THE BULK OF THE PRECIPITATION WILL BE WEST AND SOUTH OF KCVG. CONDITIONS WILL BE SOMEWHAT FAVORABLE FOR THE FORMATION OF MAINLY MVFR FOG TO LOCALLY IFR IN THE FOG PRONE AREAS. THE REASON FOR THE FOG FORMATION IS MAINLY DUE TO THE RESIDUAL MOISTURE FROM EARLIER PRECIPITATION. WINDS TONIGHT WILL BE CALM TO LIGHT SOUTHWESTERLY. AS THE LOW FROM THE WEST APPROACHES THE AREA THE BEST CHANCE FOR PRECIPITATION WILL BE KCVG AND KLUK. THUS VCSH IN THE MORNING BECOMING VCTS IN THE AFTERNOON BECOMING TEMPO TS IN THE EVENING. AS THE FRONT APPROACHES FROM THE NORTH HAVE ADDED VCSH TO THE CENTRAL OHIO TAFS FOR LATE AFTERNOON AND EVENING. IN THE KDAY AND KILN TAFS HAVE REDUCED VCTS TO VCSH AS THEY WILL BE LOCATED BETWEEN THE TWO WEATHER PRODUCING SYSTEMS. WINDS WILL BE OUT OF THE SOUTH AT LESS THAN 10 KTS ON SUNDAY. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY THROUGH THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...AR SHORT TERM...BINAU LONG TERM...JGL AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
131 AM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT OVER THE NORTHERN GREAT LAKES WILL DROP SOUTH ACROSS THE AREA LATE TONIGHT AND SUNDAY. THE FRONT WILL STALL IN CENTRAL OHIO BY SUNDAY NIGHT. LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT ON MONDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SHOWERS CONTINUE TO DEVELOP ALONG THE FRONT OVER LOWER MICHIGAN. LATEST HRRR HAS THIS ACTIVITY SPREADING SOUTH ACROSS THE LOCAL AREA OVERNIGHT. DO NOT THINK THERE WILL BE MUCH IF ANY THUNDER SO WILL OMIT FROM THE FORECAST. WILL HOWEVER...CARRY AT LEAST CHANCE POPS ALL AREAS OVERNIGHT. BEST CHANCES THROUGH MIDNIGHT WILL BE OVER FAR NE AND NW PA AND WILL CONTINUE WITH SCATTERED WORDING THERE. GIVEN CURRENT DEWPOINTS AND EXPECTED CLOUD COVER HAVE NUDGE TEMPS UP SLIGHTLY FOR LOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... THE COLD FRONT SHOULD EXTEND EAST/WEST ACROSS NRN OHIO SUNDAY MORNING AND WILL CONTINUE SOUTH OF THE AREA DURING THE DAY. ALONG AND SOUTH OF THE FRONT EXPECT SHOWERS AND THUNDERSTORMS TO FLARE UP DURING THE DAY. BROUGHT A FEW HOURS OF LIKELY POPS INTO THE FAR SOUTH DURING MID DAY WITH POPS TAPERING OFF TO THE NORTH DOWN TO A SLIGHT CHANCE ROUGHLY ALONG A KCLE-KYNG LINE. MODELS SHOW DRY AIR GETTING INTO THE FAR NORTHEAST AND WILL GO DRY THERE. NO BIG CHANCE FOR SUNDAY NIGHT...DRY NORTHEAST AND CHANCE POPS ACROSS THE SOUTHERN 2/3RDS. MONDAY LOW PRESSURE WILL TRACK ACROSS SOUTHERN/CENTRAL OHIO ALONG THE STATIONARY FRONT. MODELS AGREE THAT THE BULK OF THE PRECIP WILL REMAIN SOUTH OF THE AREA HOWEVER DO EXPECT SHOWERS AND THUNDERSTORMS TO REACH NORTH INTO THE AREA DURING THE DAY. WILL HAVE CHANCE POPS ACROSS MUCH OF THE AREA WITH LIKELY FAR SOUTH AND SLIGHT CHANCE FAR NORTH. ANY CHANGE IN THE TRACK WILL OF COURSE CHANGE THE FORECAST SIGNIFICANTLY. TUESDAY MOISTURE FROM THE LOW WILL BE MOVING EAST HOWEVER THE GFS SHOWS ANOTHER UPPER TROF CHURNING IN THE WESTERN LAKES WITH DIVERGENCE ALOFT ACROSS THE AREA SO WILL NEED TO CONTINUE WITH CHANCE POPS THROUGH THE DAY AND INTO TUESDAY NIGHT. TEMPS NEAR TO A FEW DEGREES BELOW NORMAL. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... GENERAL IDEA FOR THE THE LONG TERM WILL BE A FEW ROUNDS OF SHOWERS AND THUNDERSTORMS...POSSIBLY DRYING OUT BY THE WEEKEND. UPPER LOW OPENS UP BETWEEN WEDNESDAY AND THURSDAY AS IT PASSES ACROSS THE GREAT LAKES AND SOUTH OF A BLOCKING RIDGE ACROSS CANADA. THIS WILL TAKE A WEAK LOW ACROSS SOUTHERN ONTARIO. THIS WILL BE ENOUGH TO GIVE US ELEVATED PRECIPITATION CHANCES. WITH TIMING DIFFICULTIES...DID NOT GO ANY HIGHER THAN 30 OR 40 PERCENT. NORTHWEST UPPER FLOW IN ITS WAKE COULD STILL GIVE US INCREASED THUNDERSTORM CHANCES FOR FRIDAY...BUT GENERAL TREND IS FOR INCREASING HEIGHTS/A RIDGE TO BUILD INTO THE REGION FOR THE WEEKEND. WITH THAT HAVE TEMPERATURES THAT ARE CLOSE TO NORMAL...COMING UP A COUPLE OF DEGREES TOWARD THE WEEKEND. CLOUD COVER AND ANY MID-DAY PRECIP COULD ALTER THAT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... A COLD FRONT SINKING SOUTH ACROSS THE LAKE WILL CLIP ERI/CLE/YNG EARLY THIS MORNING WITH SHOWERS AND ISOLATED THUNDERSTORMS. INCREASED LOW LEVEL MOISTURE WILL SUPPORT IFR CONDITIONS ACROSS THE REGION DURING THE EARLY MORNING HOURS. ERI WILL BE THE FIRST TO IMPROVE AS DRIER AIR BEHIND THE FRONT ERODES THE LOW CLOUDS. CLE WILL BEGIN TO BREAK UP MID DAY. THE FRONT WILL STALL AND IT`S LOCATION WILL BE THE FOCUS FOR AFTERNOON CONVECTION. THE BEST INDICATIONS SHOW IT SAGGING JUST SOUTH OF A LINE FROM FDY TO YNG. CAN`T RULE OUT VICINITY SHRA FOR THOSE TAF SITES FOR THE BETTER PART OF THE DAY. CANNOT RULE OUT THUNDER BUT ODDS TOO LOW TO MENTION. CEILINGS WILL LIKELY DROP BACK TO MVFR OVERNIGHT. OUTLOOK...NON VFR POSSIBLE OVERNIGHT AND THEN IN SHOWERS/THUNDERSTORMS THROUGH THURSDAY. && .MARINE... STIFF SOUTHWEST FLOW WILL DECREASE OVERNIGHT AND SHIFT TO THE NNW AS A COLD FRONT COMES SOUTH...STRETCHING OUT ACROSS NORTHERN OHIO EARLY SUNDAY. SMALL CRAFT ADVISORY WILL CONTINUE FOR OFF OF ERIE THROUGH THIS EVENING AND INTO THE EARLY OVERNIGHT. HIGH PRESSURE WILL BE BUILDING NORTH OF THE LAKE FOR SUNDAY WITH A LIGHTER NORTHEAST FLOW FOR THE LAKE. THE HIGH WILL BE IN PLACE MONDAY WHILE THE NEXT SYSTEM TAKES A SOUTHERN TRACK ACROSS THE OHIO VALLEY. THE NORTHEAST FLOW MAY MAKE THE ISLAND A LITTLE CHOPPY...BUT AT THIS POINT WINDS DO NOT APPEAR STRONG ENOUGH FOR A SMALL CRAFT ADV. BEYOND MONDAY THE WEATHER PATTERN IS A BIT MORE UNSETTLED WITH A SLOW MOVING SYSTEM MAKING ITS WAY ACROSS THE GREAT LAKES THROUGH THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR LEZ149. && $$ SYNOPSIS...TK NEAR TERM...KUBINA SHORT TERM...TK LONG TERM...OUDEMAN AVIATION...JAMISON MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS NORMAN OK
1026 AM CDT SUN AUG 17 2014 .UPDATE... THE ONLY CHANGE THE FORECAST THIS MORNING WAS TO ADJUST POPS TO REFLECT RECENT RADAR TRENDS. THIS REQUIRED INCREASING POPS TO LIKELY ACROSS FAR SOUTHEASTERN PORTIONS OF THE AREA...MAINLY BRYAN COUNTY. MAX TEMPS WERE ALSO NUDGED DOWNWARD IN AREAS OF CLOUD COVER. OTHERWISE...THE FORECAST LOOKS TO BE ON TRACK. && .PREV DISCUSSION... /ISSUED 621 AM CDT SUN AUG 17 2014/ DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. AVIATION... VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED TO CONTINUE. BRIEF MVFR VISIBILITIES IN BR MAY OCCUR AT KPNC THROUGH 14Z... BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE. ISO TSRA ARE EXPECTED ACROSS THE AREA 18-02Z...MAINLY WEST AND SOUTH OF A KAVK-KOUN-KSNL LINE...BUT CHANCES OF OCCURRENCE AT ANY TAF SITE REMAINS TOO LOW TO MENTION. MBS PREV DISCUSSION... /ISSUED 358 AM CDT SUN AUG 17 2014/ DISCUSSION... THE MAIN CONCERN IS DEALING WITH HOT WEATHER...PERHAPS THE HOTTEST SO FAR THIS SUMMER...DURING THE NEXT SEVEN DAYS. ANY RAINFALL WILL REMAIN SPARSE AND LOCALIZED THROUGH NEXT SATURDAY. DID NOT ISSUE A HEAT ADVISORY AS CONFIDENCE OF HEAT INDICES EXCEEDING 105 DEGREES REMAINS RATHER LOW. SOME UNCERTAINTY REMAINS WITH FORECAST SURFACE DEWPOINTS OVER THE NEXT SEVEN DAYS...WHICH MAY DECREASE SIGNIFICANTLY AS THE GROUND DRIES OUT. TODAY WILL BE ANOTHER HOT DAY. MORE SUN WILL ALLOW FOR HOTTER READINGS ACROSS CENTRAL AND SOUTHERN OKLAHOMA AS WELL AS PARTS OF WESTERN NORTH TEXAS. USED A BLEND OF GUIDANCE HIGHS MAINLY IN THE 95 TO 103 DEGREE RANGE. THIS MORNING...A FEW LIGHT SHOWERS AND PERHAPS A RUMBLE OF THUNDER WILL CONTINUE ACROSS PARTS OF SOUTHERN AND SOUTHEASTERN OKLAHOMA. KEPT 20 TO 30 PERCENT CHANCES MAINLY SOUTH OF A WAURIKA TO ADA TO HOLDENVILLE LINE. ANY RAINFALL IS EXPECTED TO REMAIN ON THE LIGHT SIDE. THIS AFTERNOON INTO EVENING...THINK A FEW THUNDERSTORMS WILL DEVELOP DURING THE HEAT OF THE DAY IN A WEAKLY CAPPED ENVIRONMENT. LATEST HRRR HINTS AT FIRST DEVELOPMENT 1 TO 3 PM ACROSS WESTERN AND SOUTHERN OKLAHOMA...SOMEWHERE NEAR A GAGE TO HOBART TO ATOKA LINE. WENT WITH 10 TO 20 PERCENT ISOLATED MENTION WEST AND SOUTH OF AN ALVA TO CHICKASHA TO SEMINOLE LINE. ANY STORM WOULD MOVE VERY SLOWLY WITH LOCALIZED STRONG WINDS AND HEAVY RAINFALL AS THE MAIN HAZARDS...THEN DISSIPATE WITH THE LOSS OF DAYTIME HEATING. STORM COVERAGE WILL REMAIN LIMITED DUE TO VERY WEAK MID/UPPER LEVEL FORCING. MONDAY THROUGH SATURDAY...HOT AND MAINLY DRY WEATHER WILL CONTINUE WITH MID/UPPER LEVEL RIDGING. REMOVED RAIN CHANCES MONDAY THROUGH WEDNESDAY AS STORM COVERAGE WILL LIKELY REMAIN BELOW 15 PERCENT...THOUGH THERE MAY A FEW MAINLY AFTERNOON AND EVENING STORMS DURING THIS TIME FRAME. WENT FAIRLY CONSERVATIVE WITH TEMPERATURES. WIDESPREAD TRIPLE DIGIT HEAT MAY OCCUR. SURFACE WINDS WILL INCREASE BY THE MIDDLE OF THE WEEK. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 96 73 101 74 / 10 10 10 10 HOBART OK 99 73 103 74 / 10 10 10 10 WICHITA FALLS TX 99 75 103 77 / 10 10 10 10 GAGE OK 100 70 102 71 / 10 10 10 10 PONCA CITY OK 93 71 100 73 / 10 10 10 10 DURANT OK 91 74 99 76 / 60 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 84/30
AREA FORECAST DISCUSSION
NWS NORMAN OK
621 AM CDT SUN AUG 17 2014 .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED TO CONTINUE. BRIEF MVFR VISIBILITIES IN BR MAY OCCUR AT KPNC THROUGH 14Z... BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE. ISO TSRA ARE EXPECTED ACROSS THE AREA 18-02Z...MAINLY WEST AND SOUTH OF A KAVK-KOUN-KSNL LINE...BUT CHANCES OF OCCURRENCE AT ANY TAF SITE REMAINS TOO LOW TO MENTION. MBS && .PREV DISCUSSION... /ISSUED 358 AM CDT SUN AUG 17 2014/ DISCUSSION... THE MAIN CONCERN IS DEALING WITH HOT WEATHER...PERHAPS THE HOTTEST SO FAR THIS SUMMER...DURING THE NEXT SEVEN DAYS. ANY RAINFALL WILL REMAIN SPARSE AND LOCALIZED THROUGH NEXT SATURDAY. DID NOT ISSUE A HEAT ADVISORY AS CONFIDENCE OF HEAT INDICES EXCEEDING 105 DEGREES REMAINS RATHER LOW. SOME UNCERTAINTY REMAINS WITH FORECAST SURFACE DEWPOINTS OVER THE NEXT SEVEN DAYS...WHICH MAY DECREASE SIGNIFICANTLY AS THE GROUND DRIES OUT. TODAY WILL BE ANOTHER HOT DAY. MORE SUN WILL ALLOW FOR HOTTER READINGS ACROSS CENTRAL AND SOUTHERN OKLAHOMA AS WELL AS PARTS OF WESTERN NORTH TEXAS. USED A BLEND OF GUIDANCE HIGHS MAINLY IN THE 95 TO 103 DEGREE RANGE. THIS MORNING...A FEW LIGHT SHOWERS AND PERHAPS A RUMBLE OF THUNDER WILL CONTINUE ACROSS PARTS OF SOUTHERN AND SOUTHEASTERN OKLAHOMA. KEPT 20 TO 30 PERCENT CHANCES MAINLY SOUTH OF A WAURIKA TO ADA TO HOLDENVILLE LINE. ANY RAINFALL IS EXPECTED TO REMAIN ON THE LIGHT SIDE. THIS AFTERNOON INTO EVENING...THINK A FEW THUNDERSTORMS WILL DEVELOP DURING THE HEAT OF THE DAY IN A WEAKLY CAPPED ENVIRONMENT. LATEST HRRR HINTS AT FIRST DEVELOPMENT 1 TO 3 PM ACROSS WESTERN AND SOUTHERN OKLAHOMA...SOMEWHERE NEAR A GAGE TO HOBART TO ATOKA LINE. WENT WITH 10 TO 20 PERCENT ISOLATED MENTION WEST AND SOUTH OF AN ALVA TO CHICKASHA TO SEMINOLE LINE. ANY STORM WOULD MOVE VERY SLOWLY WITH LOCALIZED STRONG WINDS AND HEAVY RAINFALL AS THE MAIN HAZARDS...THEN DISSIPATE WITH THE LOSS OF DAYTIME HEATING. STORM COVERAGE WILL REMAIN LIMITED DUE TO VERY WEAK MID/UPPER LEVEL FORCING. MONDAY THROUGH SATURDAY...HOT AND MAINLY DRY WEATHER WILL CONTINUE WITH MID/UPPER LEVEL RIDGING. REMOVED RAIN CHANCES MONDAY THROUGH WEDNESDAY AS STORM COVERAGE WILL LIKELY REMAIN BELOW 15 PERCENT...THOUGH THERE MAY A FEW MAINLY AFTERNOON AND EVENING STORMS DURING THIS TIME FRAME. WENT FAIRLY CONSERVATIVE WITH TEMPERATURES. WIDESPREAD TRIPLE DIGIT HEAT MAY OCCUR. SURFACE WINDS WILL INCREASE BY THE MIDDLE OF THE WEEK. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 98 73 101 74 / 10 10 10 10 HOBART OK 101 73 103 74 / 10 10 10 10 WICHITA FALLS TX 100 75 103 77 / 10 10 10 10 GAGE OK 100 70 102 71 / 10 10 10 10 PONCA CITY OK 96 71 100 73 / 10 10 10 10 DURANT OK 96 74 99 76 / 30 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17/17
AREA FORECAST DISCUSSION
NWS NORMAN OK
358 AM CDT SUN AUG 17 2014 .DISCUSSION... THE MAIN CONCERN IS DEALING WITH HOT WEATHER...PERHAPS THE HOTTEST SO FAR THIS SUMMER...DURING THE NEXT SEVEN DAYS. ANY RAINFALL WILL REMAIN SPARSE AND LOCALIZED THROUGH NEXT SATURDAY. DID NOT ISSUE A HEAT ADVISORY AS CONFIDENCE OF HEAT INDICES EXCEEDING 105 DEGREES REMAINS RATHER LOW. SOME UNCERTAINTY REMAINS WITH FORECAST SURFACE DEWPOINTS OVER THE NEXT SEVEN DAYS...WHICH MAY DECREASE SIGNIFICANTLY AS THE GROUND DRIES OUT. TODAY WILL BE ANOTHER HOT DAY. MORE SUN WILL ALLOW FOR HOTTER READINGS ACROSS CENTRAL AND SOUTHERN OKLAHOMA AS WELL AS PARTS OF WESTERN NORTH TEXAS. USED A BLEND OF GUIDANCE HIGHS MAINLY IN THE 95 TO 103 DEGREE RANGE. THIS MORNING...A FEW LIGHT SHOWERS AND PERHAPS A RUMBLE OF THUNDER WILL CONTINUE ACROSS PARTS OF SOUTHERN AND SOUTHEASTERN OKLAHOMA. KEPT 20 TO 30 PERCENT CHANCES MAINLY SOUTH OF A WAURIKA TO ADA TO HOLDENVILLE LINE. ANY RAINFALL IS EXPECTED TO REMAIN ON THE LIGHT SIDE. THIS AFTERNOON INTO EVENING...THINK A FEW THUNDERSTORMS WILL DEVELOP DURING THE HEAT OF THE DAY IN A WEAKLY CAPPED ENVIRONMENT. LATEST HRRR HINTS AT FIRST DEVELOPMENT 1 TO 3 PM ACROSS WESTERN AND SOUTHERN OKLAHOMA...SOMEWHERE NEAR A GAGE TO HOBART TO ATOKA LINE. WENT WITH 10 TO 20 PERCENT ISOLATED MENTION WEST AND SOUTH OF AN ALVA TO CHICKASHA TO SEMINOLE LINE. ANY STORM WOULD MOVE VERY SLOWLY WITH LOCALIZED STRONG WINDS AND HEAVY RAINFALL AS THE MAIN HAZARDS...THEN DISSIPATE WITH THE LOSS OF DAYTIME HEATING. STORM COVERAGE WILL REMAIN LIMITED DUE TO VERY WEAK MID/UPPER LEVEL FORCING. MONDAY THROUGH SATURDAY...HOT AND MAINLY DRY WEATHER WILL CONTINUE WITH MID/UPPER LEVEL RIDGING. REMOVED RAIN CHANCES MONDAY THROUGH WEDNESDAY AS STORM COVERAGE WILL LIKELY REMAIN BELOW 15 PERCENT...THOUGH THERE MAY A FEW MAINLY AFTERNOON AND EVENING STORMS DURING THIS TIME FRAME. WENT FAIRLY CONSERVATIVE WITH TEMPERATURES. WIDESPREAD TRIPLE DIGIT HEAT MAY OCCUR. SURFACE WINDS WILL INCREASE BY THE MIDDLE OF THE WEEK. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 98 73 101 74 / 10 10 10 10 HOBART OK 101 73 103 74 / 10 10 10 10 WICHITA FALLS TX 100 75 103 77 / 10 10 10 10 GAGE OK 100 70 102 71 / 10 10 10 10 PONCA CITY OK 96 71 100 73 / 10 10 10 10 DURANT OK 96 74 99 76 / 30 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17
AREA FORECAST DISCUSSION
NWS PENDLETON OR
1050 AM PDT SUN AUG 17 2014 UPDATED THE AVIATION DISCUSSION .UPDATE...TODAY AND TONIGHT...AN UPPER LEVEL LOW PRESENTLY MOVING SOUTH ALONG THE WASHINGTON COASTLINE WILL CONTINUE TO MOVE SOUTH DURING THE PERIOD. THE BEST DYNAMICS ASSOCIATED WITH THIS UPPER LOW REMAINS ON THE WEST SIDE OF THE SYSTEM...WHICH IS OFFSHORE AND AWAY FROM OUR AREA. HOWEVER...THE HEATING OF THE DAY WILL COMBINE WITH THE LIFT PROVIDED BY THE LOW TO CAUSE SOME ISOLATED TO SCATTERED THUNDERSTORMS OVER THE EAST SLOPES OF THE CASCADES...CENTRAL OREGON...THE JOHN DAY HIGHLANDS AND THE SOUTHERN BLUE MOUNTAINS. HAVE OPTED TO INDICATE THE BEST CHANCES OF THUNDERSTORMS TO BE LATE THIS AFTERNOON INTO EARLY EVENING GIVEN HRRR AND LATEST MODEL GUIDANCE. HAVE ALSO ADJUSTED THE SKY GRIDS TO ACCOUNT FOR THE EXPECTED CLOUD COVER WITH THESE THUNDERSTORMS. OTHERWISE...OUTSIDE OF MINOR TWEAKS TO TEMPERATURE GRIDS...THE FORECAST REMAINS ON TRACK. BIEDA .AVIATION...MOSTLY VFR CONDITIONS WILL PERSIST FOR THE NEXT 24 HOURS EXCEPT FOR TAF SITES KRDM AND KBDN WHICH COULD APPROACH LCL MVFR CEILINGS IN AND NEAR TSRA BETWEEN 20Z AND 04Z. && .PREV DISC... /ISSUED 249 AM PDT SUN AUG 17 2014/ SHORT TERM...TODAY THROUGH MONDAY NIGHT...A WEAK UPPER LOW OVER VANCOUVER ISLAND EARLY THIS MORNING WILL SLIDE SOUTH TODAY, CUTTING OFF NEAR ASTORIA BY LATE AFTERNOON. THIS LOW WILL SLIDE SOUTH ALONG THE COAST THROUGH THE REMAINDER OF THE PERIOD REACHING TO NEAR CAPE BLANCO MONDAY MORNING THEN SOUTHWEST OF THE SAN FRANCISCO BAY AREA BY EARLY TUESDAY MORNING. THE BEST DYNAMIC ENERGY WITH THIS SYSTEM WILL REMAIN ON THE WEST SIDE OF THE LOW AND OVER THE COASTAL WATERS. THIS WILL LIMIT THE CONTRIBUTION DYNAMIC ENERGY WILL ADD TO THE POTENTIAL FOR THUNDERSTORM DEVELOPMENT THROUGH THIS PERIOD. ALSO SHEAR ACROSS THE REGION WILL BE WEAK, LESS THAN 25 KTS. MOISTURE WILL ALSO BE SOMEWHAT LIMITED, ESPECIALLY ACROSS SOUTHEAST WASHINGTON AND EXTREME NORTHEAST OREGON ON MONDAY WHERE DRY WESTERLY FLOW WILL RETURN. MEANWHILE DAYTIME HIGH TEMPS WILL RUN FROM THE LOW 80S TO LOW 90S, THUS HEATING WILL BE SUFFICIENT TO WORK ON THE MOISTURE THAT IS AVAILABLE AND CAUSE SOME CONVECTIVE DEVELOPMENT. OVERALL, WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS FROM CENTRAL OREGON EAST TO GRANT COUNTY AND THE SOUTHERN BLUES TODAY AND MONDAY. THESE AREAS WILL SEE SOME DIFFLUENCE ALOFT AND WILL HAVE THE DEEPEST MOISTURE. WILL ALSO CONTINUE A SLIGHT CHANCE OVER THE WALLOWA MOUNTAINS EACH DAY DUE TO CONVERGENT UPSLOPE/UP VALLEY WINDS. WILL ALSO ADD A SLIGHT CHANCE OF STORMS TO THE CENTRAL WASHINGTON CASCADE EAST SLOPES TODAY DUE TO THE LOW PASSING BY TO THE WEST AND SOME LOW LEVEL UPSLOPE FLOW THIS AFTERNOON. 90 LONG TERM...TUESDAY THROUGH SATURDAY...TUESDAY A TROUGH WILL DEVELOP OVER THE PACIFIC NORTHWEST WITH A PACIFIC COLD FRONT MOVING THROUGH THE AREA DURING THE AFTERNOON. CONDITIONS WILL BECOME BREEZY BEHIND THE FRONT...ESPECIALLY IN THE COLUMBIA BASIN AND CASCADE GAPS. THE MAIN LIFT FROM THE TROUGH WILL REMAIN IN CANADA SO PRECIPITATION WILL BE LIMITED TO OROGRAPHICALLY ENHANCED SHOWERS OVER THE EAST SLOPES OF THE CASCADES AND THE BLUE MOUNTAINS. A BROAD TROUGH WILL REMAIN OVER THE PACIFIC NORTHWEST WEDNESDAY THROUGH FRIDAY. EMBEDDED IMPULSES WITHIN THE FLOW MAY TRIGGER SOME SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD...BUT MODELS ARE INCONSISTENT ON TIMING AND LOCATION OF THESE IMPULSES. WITH LIMITED CONFIDENCE DID NOT CHANGE EXISTING FORECAST OF SLIGHT CHANCE OF DIURNALLY AND OROGRAPHICALLY ENHANCED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. COONFIELD && .PRELIMINARY POINT TEMPS/POPS... PDT 89 62 92 62 / 0 10 10 10 ALW 90 67 93 67 / 0 10 10 10 PSC 92 64 95 64 / 0 10 0 0 YKM 89 62 92 62 / 0 10 0 0 HRI 92 63 94 62 / 0 10 0 0 ELN 91 66 94 61 / 10 10 0 0 RDM 88 53 90 54 / 20 20 20 20 LGD 87 53 90 54 / 10 10 10 10 GCD 89 59 92 58 / 20 20 20 10 DLS 92 65 95 66 / 0 10 10 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 98/97
AREA FORECAST DISCUSSION
NWS PENDLETON OR
835 AM PDT SUN AUG 17 2014 .UPDATE...TODAY AND TONIGHT...AN UPPER LEVEL LOW PRESENTLY MOVING SOUTH ALONG THE WASHINGTON COASTLINE WILL CONTINUE TO MOVE SOUTH DURING THE PERIOD. THE BEST DYNAMICS ASSOCIATED WITH THIS UPPER LOW REMAINS ON THE WEST SIDE OF THE SYSTEM...WHICH IS OFFSHORE AND AWAY FROM OUR AREA. HOWEVER...THE HEATING OF THE DAY WILL COMBINE WITH THE LIFT PROVIDED BY THE LOW TO CAUSE SOME ISOLATED TO SCATTERED THUNDERSTORMS OVER THE EAST SLOPES OF THE CASCADES...CENTRAL OREGON...THE JOHN DAY HIGHLANDS AND THE SOUTHERN BLUE MOUNTAINS. HAVE OPTED TO INDICATE THE BEST CHANCES OF THUNDERSTORMS TO BE LATE THIS AFTERNOON INTO EARLY EVENING GIVEN HRRR AND LATEST MODEL GUIDANCE. HAVE ALSO ADJUSTED THE SKY GRIDS TO ACCOUNT FOR THE EXPECTED CLOUD COVER WITH THESE THUNDERSTORMS. OTHERWISE...OUTSIDE OF MINOR TWEAKS TO TEMPERATURE GRIDS...THE FORECAST REMAINS ON TRACK. BIEDA && .PREV DISC... /ISSUED 249 AM PDT SUN AUG 17 2014/ SHORT TERM...TODAY THROUGH MONDAY NIGHT...A WEAK UPPER LOW OVER VANCOUVER ISLAND EARLY THIS MORNING WILL SLIDE SOUTH TODAY, CUTTING OFF NEAR ASTORIA BY LATE AFTERNOON. THIS LOW WILL SLIDE SOUTH ALONG THE COAST THROUGH THE REMAINDER OF THE PERIOD REACHING TO NEAR CAPE BLANCO MONDAY MORNING THEN SOUTHWEST OF THE SAN FRANCISCO BAY AREA BY EARLY TUESDAY MORNING. THE BEST DYNAMIC ENERGY WITH THIS SYSTEM WILL REMAIN ON THE WEST SIDE OF THE LOW AND OVER THE COASTAL WATERS. THIS WILL LIMIT THE CONTRIBUTION DYNAMIC ENERGY WILL ADD TO THE POTENTIAL FOR THUNDERSTORM DEVELOPMENT THROUGH THIS PERIOD. ALSO SHEAR ACROSS THE REGION WILL BE WEAK, LESS THAN 25 KTS. MOISTURE WILL ALSO BE SOMEWHAT LIMITED, ESPECIALLY ACROSS SOUTHEAST WASHINGTON AND EXTREME NORTHEAST OREGON ON MONDAY WHERE DRY WESTERLY FLOW WILL RETURN. MEANWHILE DAYTIME HIGH TEMPS WILL RUN FROM THE LOW 80S TO LOW 90S, THUS HEATING WILL BE SUFFICIENT TO WORK ON THE MOISTURE THAT IS AVAILABLE AND CAUSE SOME CONVECTIVE DEVELOPMENT. OVERALL, WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS FROM CENTRAL OREGON EAST TO GRANT COUNTY AND THE SOUTHERN BLUES TODAY AND MONDAY. THESE AREAS WILL SEE SOME DIFFLUENCE ALOFT AND WILL HAVE THE DEEPEST MOISTURE. WILL ALSO CONTINUE A SLIGHT CHANCE OVER THE WALLOWA MOUNTAINS EACH DAY DUE TO CONVERGENT UPSLOPE/UP VALLEY WINDS. WILL ALSO ADD A SLIGHT CHANCE OF STORMS TO THE CENTRAL WASHINGTON CASCADE EAST SLOPES TODAY DUE TO THE LOW PASSING BY TO THE WEST AND SOME LOW LEVEL UPSLOPE FLOW THIS AFTERNOON. 90 LONG TERM...TUESDAY THROUGH SATURDAY...TUESDAY A TROUGH WILL DEVELOP OVER THE PACIFIC NORTHWEST WITH A PACIFIC COLD FRONT MOVING THROUGH THE AREA DURING THE AFTERNOON. CONDITIONS WILL BECOME BREEZY BEHIND THE FRONT...ESPECIALLY IN THE COLUMBIA BASIN AND CASCADE GAPS. THE MAIN LIFT FROM THE TROUGH WILL REMAIN IN CANADA SO PRECIPITATION WILL BE LIMITED TO OROGRAPHICALLY ENHANCED SHOWERS OVER THE EAST SLOPES OF THE CASCADES AND THE BLUE MOUNTAINS. A BROAD TROUGH WILL REMAIN OVER THE PACIFIC NORTHWEST WEDNESDAY THROUGH FRIDAY. EMBEDDED IMPULSES WITHIN THE FLOW MAY TRIGGER SOME SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD...BUT MODELS ARE INCONSISTENT ON TIMING AND LOCATION OF THESE IMPULSES. WITH LIMITED CONFIDENCE DID NOT CHANGE EXISTING FORECAST OF SLIGHT CHANCE OF DIURNALLY AND OROGRAPHICALLY ENHANCED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. COONFIELD AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS AT MOST TAF LOCATIONS. MOISTURE AND INSTABILITY COMBINED WITH AFTERNOON HEATING MAY TRIGGER A FEW THUNDERSTORMS NEAR KRDM AND KBDN BETWEEN 21Z AND 04Z. WINDS WILL INCREASE TO 10 TO 15 KTS WITH HIGHER GUSTS DURING THE AFTERNOON IN ALL AREAS...ESPECIALLY AT KRDM...KBDN AND KDLS. 76 && .PRELIMINARY POINT TEMPS/POPS... PDT 89 62 92 62 / 0 10 10 10 ALW 90 67 93 67 / 0 10 10 10 PSC 92 64 95 64 / 0 10 0 0 YKM 89 62 92 62 / 0 10 0 0 HRI 92 63 94 62 / 0 10 0 0 ELN 91 66 94 61 / 10 10 0 0 RDM 88 53 90 54 / 20 20 20 20 LGD 87 53 90 54 / 10 10 10 10 GCD 89 59 92 58 / 20 20 20 10 DLS 92 65 95 66 / 0 10 10 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 98/76/76
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1129 AM EDT SUN AUG 17 2014 .SYNOPSIS... A WEAK FRONTAL BOUNDARY WILL PUSH TO OUR SOUTH TODAY. ANOTHER WAVE IN THE UPPER- LEVEL NORTHWESTERLY FLOW WILL PULL THIS BOUNDARY BACK INTO OUR REGION MONDAY INTO TUESDAY INCREASING THE CHANCE OF RAIN. THE NORTHWESTERLY FLOW WILL WEAKEN BUT REMAIN OVER THE REGION...TRAPPED BENEATH A HIGH LATITUDE BLOCK. MOISTURE AND A FRONTAL BOUNDARY JUST TO OUR SOUTH WILL LIKELY PRODUCE PERIODS OF UNSETTLED WEATHER UNTIL THE HIGH LATITUDE BLOCK WEAKENS. && .NEAR TERM /THROUGH TONIGHT/... USING HRRR AND RADAR PUT HIGH POPS AND RAIN IN SE MAXIMIZED OVER LANCASTER FOR NEXT 1-2 HOURS THEN DROPPED POPS. TRIED TO SHOW BASED ON RADAR...THE RAIN MOVING ACROSS SOUTHWEST MOUNTAINS IN NEXT 1-2 HOURS. VERY LIGHT RAIN IN SW. AFTER THAT POPS WITH CHANCE AND SLIGHT CHANCE FOCUSED NEAR MD BORDER. MAINLY PARTLY TO MOSTLY CLOUDY CENTRAL AND NORTHERN AREAS. CONVECTIVE ALLOWING MODELS SEEM TO SUGGEST ALL ORGANIZED RAIN OUT OF OUR AREA BY ABOUT NOON. THEN ONLY MINOR BUMPINESS IMPLYING WEAK CONVECTION...LESS IN EACH RUN AND MAINLY SOUTH AND EAST OF OUR AREA. SHOULD BE A PRETTY GOOD AFTERNOON ACROSS THE REGION WITH ANY ISOLATED RESIDUAL SHOWERS IN AFTERNOON IN SOUTHERN AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... QUIET OVERNIGHT IN A RELATIVE SENSE AND NO WEATHER TO MENTION. PATCHY FOG WITH MOISTURE FROM LIGHT RAINS THAT AFFECTED THE REGION TODAY. THE SREF AND GEFS AND A BLEND SUGGEST RAIN MOVES INTO SOUTHWEST PA MONDAY. SREF PDF IMPLIES RAIN IN OUR SOUTHWEST COUNTIES AT SLIGHT CHANCE LEVEL BY LATE MORNING THEN CHANCE BY EARLY AFTERNOON. THIS SPREADS SLOWLY TO THE NORTHEAST. THE WESTERN THIRD OF OUR REGION SHOULD BE IN CHANCE SHOWERS/RAIN BY EVENING MONDAY. THE EASTERN AREAS SHOULD STAY DRY UNTIL THE OVERNIGHT PERIOD. IF ONE BELIEVES THE 3-HOUR INCREMENTS IN THE SREF AND 6-HOUR INCREMENTS IN THE GEFS. RAIN IS LIKELY IN EXTREME SOUTHEAST BY MID-LATE AFTERNOON. GENERALLY SLOW EVOLUTION OF PRECIPITATION SHIELD. KEY POINT: NICE OVERNIGHT PARTIAL CLEARING. MOSTLY SUNNY WEST AND NORTH WITH CLOUDS RAIN COMING INTO SOUTHWEST. MOST EAST AND NORTHEAST AREAS SHOULD HAVE A PRETTY GOOD DAY. SOMERSET COUNTY SHOULD BE THE WETTEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OFF WITH A WEAK SFC LOW AND ASSOCD FRONTAL SYSTEM TRACKING EWD THRU THE GRT LKS WED-FRI. THIS WILL KEEP THE PATTERN UNSETTLED AND POTENTIALLY WET DURING THE SECOND HALF OF THE WORK WEEK. FOR NOW IT APPEARS A DRYING TREND WILL START THE WEEKEND WITH HIGH PRESSURE TAKING UP RESIDENCE IN NRN NEW ENGLAND. BLOCKING OVER ATLANTIC CANADA AND GREENLAND SHOULD ALLOW FOR THE BERMUDA HIGH AND SOUTHEAST RIDGE TO BUILD WWD INTO THE TN AND LWR MS VLYS...WHILE EASTERLY COMPNT TO THE LLVL FLOW TEMPERS HIGHS DESPITE RISING HGTS ALOFT. A CONSENSUS BLEND OF WPC WITH GFS AND ECMWF MOS BASED PRODUCTS FAVORS NEAR OR JUST BLW CLIMO NUMBERS FOR MID-LATE AUGUST. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... RESIDUAL SHOWERS MOVING OUT OF LANCASTER COUNTY TO POINTS EAST AND ISOLATED SHOWERS IN SOUTHWEST MOUNTAINS WEAKENING. EXPECT ALL AREAS TO CLIMB TO VFR IN THE NEXT HOUR OR SO. VFR SHOULD DOMINATE THE REGION THIS AFTERNOON AND EVENING. PATCHY FOG OVERNIGHT WILL BRING REGIONS OF IFR/MVFR. BETTER RADIATIONAL COOLING LOCATIONS WHERE IT RAINED WILL LIKELY GENERATE ISOLATED AREAS OF LIFR AFTER MIDNIGHT AND A FEW HOURS AFTER SUNRISE MONDAY. MOSTLY VFR MONDAY...EXCEPT MVFR MOVING INTO SOUTHWEST AS NEXT FRONTAL SYSTEM SPREADS RAIN SOUTHWEST TO NORTHEAST ACROSS THE STATE MONDAY IN THE AFTERNOON AND INTO THE EVENING. CONDITIONS IMPROVE AGAIN TUESDAY INTO WEDNESDAY EXCEPT FOR OVERNIGHT PATCHY FOG ISSUES. OUTLOOK... MON...AM FOG POSS N MTNS. SLIGHT CHC OF PM TSRA IMPACTS KJST/KAOO. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA FIRST HALF DAY. WED-THU...AM FOG POSS. SCT PM TSRA IMPACTS POSS W MTNS...ESP W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...STEINBUGL AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1116 AM EDT SUN AUG 17 2014 .SYNOPSIS... A WEAK FRONTAL BOUNDARY WILL PUSH TO OUR SOUTH TODAY. ANOTHER WAVE IN THE UPPER- LEVEL NORTHWESTERLY FLOW WILL PULL THIS BOUNDARY BACK INTO OUR REGION MONDAY INTO TUESDAY INCREASING THE CHANCE OF RAIN. THE NORTHWESTERLY FLOW WILL WEAKEN BUT REMAIN OVER THE REGION...TRAPPED BENEATH A HIGH LATITUDE BLOCK. MOISTURE AND A FRONTAL BOUNDARY JUST TO OUR SOUTH WILL LIKELY PRODUCE PERIODS OF UNSETTLED WEATHER UNTIL THE HIGH LATITUDE BLOCK WEAKENS. && .NEAR TERM /THROUGH TONIGHT/... USING HRRR AND RADAR PUT HIGH POPS AND RAIN IN SE MAXIMIZED OVER LANCASTER FOR NEXT 1-2 HOURS THEN DROPPED POPS. TRIED TO SHOW BASED ON RADAR...THE RAIN MOVING ACROSS SOUTHWEST MOUNTAINS IN NEXT 1-2 HOURS. VERY LIGHT RAIN IN SW. AFTER THAT POPS WITH CHANCE AND SLIGHT CHANCE FOCUSED NEAR MD BORDER. MAINLY PARTLY TO MOSTLY CLOUDY CENTRAL AND NORTHERN AREAS. CONVECTIVE ALLOWING MODELS SEEM TO SUGGEST ALL ORGANIZED RAIN OUT OF OUR AREA BY ABOUT NOON. THEN ONLY MINOR BUMPINESS IMPLYING WEAK CONVECTION...LESS IN EACH RUN AND MAINLY SOUTH AND EAST OF OUR AREA. SHOULD BE A PRETTY GOOD AFTERNOON ACROSS THE REGION WITH ANY ISOLATED RESIDUAL SHOWERS IN AFTERNOON IN SOUTHERN AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... QUIET OVERNIGHT IN A RELATIVE SENSE AND NO WEATHER TO MENTION. PATCHY FOG WITH MOISTURE FROM LIGHT RAINS THAT AFFECTED THE REGION TODAY. THE SREF AND GEFS AND A BLEND SUGGEST RAIN MOVES INTO SOUTHWEST PA MONDAY. SREF PDF IMPLIES RAIN IN OUR SOUTHWEST COUNTIES AT SLIGHT CHANCE LEVEL BY LATE MORNING THEN CHANCE BY EARLY AFTERNOON. THIS SPREADS SLOWLY TO THE NORTHEAST. THE WESTERN THIRD OF OUR REGION SHOULD BE IN CHANCE SHOWERS/RAIN BY EVENING MONDAY. THE EASTERN AREAS SHOULD STAY DRY UNTIL THE OVERNIGHT PERIOD. IF ONE BELIEVES THE 3-HOUR INCREMENTS IN THE SREF AND 6-HOUR INCREMENTS IN THE GEFS. RAIN IS LIKELY IN EXTREME SOUTHEAST BY MID-LATE AFTERNOON. GENERALLY SLOW EVOLUTION OF PRECIPITATION SHIELD. KEY POINT: NICE OVERNIGHT PARTIAL CLEARING. MOSTLY SUNNY WEST AND NORTH WITH CLOUDS RAIN COMING INTO SOUTHWEST. MOST EAST AND NORTHEAST AREAS SHOULD HAVE A PRETTY GOOD DAY. SOMERSET COUNTY SHOULD BE THE WETTEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OFF WITH A WEAK SFC LOW AND ASSOCD FRONTAL SYSTEM TRACKING EWD THRU THE GRT LKS WED-FRI. THIS WILL KEEP THE PATTERN UNSETTLED AND POTENTIALLY WET DURING THE SECOND HALF OF THE WORK WEEK. FOR NOW IT APPEARS A DRYING TREND WILL START THE WEEKEND WITH HIGH PRESSURE TAKING UP RESIDENCE IN NRN NEW ENGLAND. BLOCKING OVER ATLANTIC CANADA AND GREENLAND SHOULD ALLOW FOR THE BERMUDA HIGH AND SOUTHEAST RIDGE TO BUILD WWD INTO THE TN AND LWR MS VLYS...WHILE EASTERLY COMPNT TO THE LLVL FLOW TEMPERS HIGHS DESPITE RISING HGTS ALOFT. A CONSENSUS BLEND OF WPC WITH GFS AND ECMWF MOS BASED PRODUCTS FAVORS NEAR OR JUST BLW CLIMO NUMBERS FOR MID-LATE AUGUST. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... A WEAKENING COLD FRONT WILL PUSH SE ACROSS THE AREA OVERNIGHT... ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF PRE-DAWN LOW CIGS AT KBFD...CAUSED BY POST-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA AND MOISTENING CAUSED BY SHOWERS NOW OCCURRING. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z- 14Z TIME FRAME. FARTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIGNIFICANT RESTRICTIONS MUCH LESS LIKELY. THE COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING THE DAY TODAY. ANY LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION. OUTLOOK... MON...AM FOG POSS N MTNS. SLIGHT CHC OF PM TSRA IMPACTS KJST/KAOO. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED-THU...AM FOG POSS. SCT PM TSRA IMPACTS POSS W MTNS...ESP W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1049 AM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT MOVING SOUTHEAST FROM LAKE ERIE WILL CONTINUE TO PUSH THROUGH CENTRAL PENNSYLVANIA BY TONIGHT BEFORE BECOMING NEARLY STATIONARY SOUTH OF THE MASON DIXON LINE. WAVES OF LOW PRESSURE MOVING EAST FROM THE OHIO VALLEY ALONG THE FRONTAL ZONE WILL BRING PERIODS OF RAIN TO THE AREA THROUGH MUCH OF THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... USING HRRR AND RADAR PUT HIGH POPS AND RAIN IN SE MAXIMIZED OVER LANCASTER FOR NEXT 1-2 HOURS THEN DROPPED POPS. TRIED TO SHOW BASED ON RADAR...THE RAIN MOVING ACROSS SOUTHWEST MOUNTAINS IN NEXT 1-2 HOURS. VERY LIGHT RAIN IN SW. AFTER THAT POPS WITH CHANCE AND SLIGHT CHANCE FOCUSED NEAR MD BORDER. MAINLY PARTLY TO MOSTLY CLOUDY CENTRAL AND NORTHERN AREAS. CONVECTIVE ALLOWING MODELS SEEM TO SUGGEST ALL ORGANIZED RAIN OUT OF OUR AREA BY ABOUT NOON. THEN ONLY MINOR BUMPINESS IMPLYING WEAK CONVECTION...LESS IN EACH RUN AND MAINLY SOUTH AND EAST OF OUR AREA. SHOULD BE A PRETTY GOOD AFTERNOON ACROSS THE REGION WITH ANY ISOLATED RESIDUAL SHOWERS IN AFTERNOON IN SOUTHERN AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... QUIET OVERNIGHT IN A RELATIVE SENSE AND NO WEATHER TO MENTION. PATCHY FOG WITH MOISTURE FROM LIGHT RAINS THAT AFFECTED THE REGION TODAY. THE SREF AND GEFS AND A BLEND SUGGEST RAIN MOVES INTO SOUTHWEST PA MONDAY. SREF PDF IMPLIES RAIN IN OUR SOUTHWEST COUNTIES AT SLIGHT CHANCE LEVEL BY LATE MORNING THEN CHANCE BY EARLY AFTERNOON. THIS SPREADS SLOWLY TO THE NORTHEAST. THE WESTERN THIRD OF OUR REGION SHOULD BE IN CHANCE SHOWERS/RAIN BY EVENING MONDAY. THE EASTERN AREAS SHOULD STAY DRY UNTIL THE OVERNIGHT PERIOD. IF ONE BELIEVES THE 3-HOUR INCREMENTS IN THE SREF AND 6-HOUR INCREMENTS IN THE GEFS. RAIN IS LIKELY IN EXTREME SOUTHEAST BY MID-LATE AFTERNOON. GENERALLY SLOW EVOLUTION OF PRECIPITATION SHIELD. KEY POINT: NICE OVERNIGHT PARTIAL CLEARING. MOSTLY SUNNY WEST AND NORTH WITH CLOUDS RAIN COMING INTO SOUTHWEST. MOST EAST AND NORTHEAST AREAS SHOULD HAVE A PRETTY GOOD DAY. SOMERSET COUNTY SHOULD BE THE WETTEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OFF WITH A WEAK SFC LOW AND ASSOCD FRONTAL SYSTEM TRACKING EWD THRU THE GRT LKS WED-FRI. THIS WILL KEEP THE PATTERN UNSETTLED AND POTENTIALLY WET DURING THE SECOND HALF OF THE WORK WEEK. FOR NOW IT APPEARS A DRYING TREND WILL START THE WEEKEND WITH HIGH PRESSURE TAKING UP RESIDENCE IN NRN NEW ENGLAND. BLOCKING OVER ATLANTIC CANADA AND GREENLAND SHOULD ALLOW FOR THE BERMUDA HIGH AND SOUTHEAST RIDGE TO BUILD WWD INTO THE TN AND LWR MS VLYS...WHILE EASTERLY COMPNT TO THE LLVL FLOW TEMPERS HIGHS DESPITE RISING HGTS ALOFT. A CONSENSUS BLEND OF WPC WITH GFS AND ECMWF MOS BASED PRODUCTS FAVORS NEAR OR JUST BLW CLIMO NUMBERS FOR MID-LATE AUGUST. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... A WEAKENING COLD FRONT WILL PUSH SE ACROSS THE AREA OVERNIGHT... ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF PRE-DAWN LOW CIGS AT KBFD...CAUSED BY POST-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA AND MOISTENING CAUSED BY SHOWERS NOW OCCURRING. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z- 14Z TIME FRAME. FARTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIGNIFICANT RESTRICTIONS MUCH LESS LIKELY. THE COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING THE DAY TODAY. ANY LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION. OUTLOOK... MON...AM FOG POSS N MTNS. SLIGHT CHC OF PM TSRA IMPACTS KJST/KAOO. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED-THU...AM FOG POSS. SCT PM TSRA IMPACTS POSS W MTNS...ESP W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 AM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT MOVING SOUTHEAST FROM LAKE ERIE WILL CONTINUE TO PUSH THROUGH CENTRAL PENNSYLVANIA BY TONIGHT BEFORE BECOMING NEARLY STATIONARY SOUTH OF THE MASON DIXON LINE. WAVES OF LOW PRESSURE MOVING EAST FROM THE OHIO VALLEY ALONG THE FRONTAL ZONE WILL BRING PERIODS OF RAIN TO THE AREA THROUGH MUCH OF THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... A BAND OF RAIN OVER CENTRAL PA TO NEARLY THE MARYLAND BORDER IS SAGGING SLOWLY TO THE SOUTH AND EAST. IT WILL BE A RELATIVELY WET FIRST HALF OF THE MORNING IN MOST OF CENTRAL PA AS CORES OF SHOWERS MOVE EAST ALONG THE SAGGING BOUNDARY. MOST RAIN SHOULD END AROUND NOON. EARLIER NORTH LATER SOUTH. THE VISUAL SATELLITE IMAGERY SHOWS A BREAK IN THE CLOUDS OVER THE NORTHEASTERN TIER OF THE STATE IT TOO IS SAGGING SOUTH...BUT SOME MORE LOW CLOUDS IN NEW YORK ARE LINED UP TO REPLACE THEM. THE CLEAR AREA WILL PROVIDE SOME PEAKS OF SUN AS IT MOVES SOUTH. THE LATEST 3KM HRRR IS AGGRESSIVE GETTING ALL THE RAIN TO OUR EAST BY NOON (16Z). THIS IS CLOSE TO LINEAR EXTRAPOLATION SHOULD NO NEW SHOWERS EVOLVE. CONDITIONS SHOULD IMPROVE NORTHWEST TO SOUTHEAST TODAY. LESS ACTIVITY BUT WITH SOME PEAKS OF SUN...SHOWERS COULD HAVE ISOLATED THUNDERSTORMS POSSIBLE NORTH OF THE BOUNDARY. THE HRRR SHOWS ISOLATED SHOWERS AND THUNDER LOOK TO IT SOUTHERN PA AND MD SO KEPT LOW POPS IN SOUTHERN AREAS INTO EVENING. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... UPDATED FORECAST A BIT WITH ONLY MINOR CHANGES TO TEMPS AND POPS. BUT THE RAIN POTENTIAL WILL SLOWLY INCREASE MONDAY INTO MONDAY NIGHT FROM SOUTHWEST. THE GEFS/SREF WOULD IMPLY CHANCE RAIN MOST OF SOUTHERN PA BY MONDAY AFTERNOON. PREVIOUS: A WAVE OF LOW PRESSURE WILL TRACK EWD FROM THE OH VLY ALONG THE Q-STNRY FRONTAL BOUNDARY DRAPED ACRS THE CNTRL APPLCHNS ON D2 AND SHOULD REACH THE VA/DELMARVA COAST AROUND 12Z TUE. A N-S GRADIENT OF PWS WILL EXIST OVER THE AREA WITH THE BEST MSTR /1.5+ INCH PWATS/ POOLING FROM SRN PA SWD INTO THE SRN MID ATLANTIC AND SOUTHEAST STATES. WAA/ISENT LIFT ALONG WITH INCR ESELY LLVL INFLOW SHOULD BRING RAIN INTO AT LEAST THE SRN PARTS OF THE REGION WITH GLOBAL MODELS AND ENSEMBLE DATA DEPICTING THE HIGHEST QPF AMTS OVER NRN VA BLUE RIDGE/WV PNHDL/XTRME S-CNTRL PA. THERE IS A LARGE SPREAD IN THE GUIDANCE CONCERNING THE EVOLUTION OF THE LOW AS IT MOVES OFFSHORE BY 12Z WED. MEANWHILE...THE NEXT H5 S/WV TROUGH STARTS TO CROSS THE GRT LKS REGION WITH AN ACCOMPANYING SFC LOW OF ITS OWN REACHING LK MI VCNTY BY THE END OF THE PERIOD. THIS FRONTAL SYSTEM SHOULD BRING RAIN INTO THE AREA THRU MID-WEEK. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OFF WITH A WEAK SFC LOW AND ASSOCD FRONTAL SYSTEM TRACKING EWD THRU THE GRT LKS WED-FRI. THIS WILL KEEP THE PATTERN UNSETTLED AND POTENTIALLY WET DURING THE SECOND HALF OF THE WORK WEEK. FOR NOW IT APPEARS A DRYING TREND WILL START THE WEEKEND WITH HIGH PRESSURE TAKING UP RESIDENCE IN NRN NEW ENGLAND. BLOCKING OVER ATLANTIC CANADA AND GREENLAND SHOULD ALLOW FOR THE BERMUDA HIGH AND SOUTHEAST RIDGE TO BUILD WWD INTO THE TN AND LWR MS VLYS...WHILE EASTERLY COMPNT TO THE LLVL FLOW TEMPERS HIGHS DESPITE RISING HGTS ALOFT. A CONSENSUS BLEND OF WPC WITH GFS AND ECMWF MOS BASED PRODUCTS FAVORS NEAR OR JUST BLW CLIMO NUMBERS FOR MID-LATE AUGUST. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... A WEAKENING COLD FRONT WILL PUSH SE ACROSS THE AREA OVERNIGHT... ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF PRE-DAWN LOW CIGS AT KBFD...CAUSED BY POST-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA AND MOISTENING CAUSED BY SHOWERS NOW OCCURRING. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z- 14Z TIME FRAME. FARTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIGNIFICANT RESTRICTIONS MUCH LESS LIKELY. THE COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING THE DAY TODAY. ANY LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION. OUTLOOK... MON...AM FOG POSS N MTNS. SLIGHT CHC OF PM TSRA IMPACTS KJST/KAOO. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED-THU...AM FOG POSS. SCT PM TSRA IMPACTS POSS W MTNS...ESP W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...GRUMM/STEINBUGL SHORT TERM...GRUMM/STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
527 AM EDT SUN AUG 17 2014 .SYNOPSIS... A COLD FRONT MOVING SOUTHEAST FROM LAKE ERIE WILL CONTINUE TO PUSH THROUGH CENTRAL PENNSYLVANIA BY TONIGHT BEFORE BECOMING NEARLY STATIONARY SOUTH OF THE MASON DIXON LINE. WAVES OF LOW PRESSURE MOVING EAST FROM THE OHIO VALLEY ALONG THE FRONTAL ZONE WILL BRING PERIODS OF RAIN TO THE AREA THROUGH MUCH OF THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... A NARROW BAND OF FRONTAL SHOWERS CURRENTLY LOCATED JUST SOUTH OF THE I-80 CORRIDOR WILL CONTINUE TO DROP SEWD ACROSS S-CENTRAL PA EARLY THIS MORNING. THE LATEST HRRR SHOWS THE BAND REACHING THE PA TURNPIKE AROUND 12-13Z WITH DEC CVRG OVER THE SRN ZONES THRU THE MORNING HOURS. IR STLT LOOP SHOWS A POST-FRONTAL LOW STRATUS CLOUD DECK WORKING INTO NRN PA IN THE WAKE OF THE COLD FRONT. STILL EXPECT DRY WX TO PREVAIL OVER THIS AREA TODAY BUT WILL NEED TO INCREASE SKY COVER THIS MORNING. A LOW RISK FOR SCT SHOWERS AND ISOLD TSTMS /20-30 PCT AT BEST/ WILL REMAIN THRU THE AFTN HOURS IN THE SRN TIER ZONES INVOF THE BOUNDARY. MAX TEMPS WILL BE SLIGHTLY BELOW NORMAL FOR MID-AUG IN THE LOW 70S NORTH TO AROUND 80F IN THE LOWER SUSQ. VLY. THE FRONT BECOMES Q-STNRY SOUTH OF THE MASON DIXON LINE TONIGHT. CLEARING/LGT WINDS IN THE NORTH ALONG WITH LOW PWS SHOULD ALLOW TEMPS TO DROP TO AROUND 50F WITH WARMER READINGS AROUND 60F OVER SRN PA WHERE CLOUD COVER SHOULD MORE EXPANSIVE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... A WAVE OF LOW PRESSURE WILL TRACK EWD FROM THE OH VLY ALONG THE Q-STNRY FRONTAL BOUNDARY DRAPED ACRS THE CNTRL APPLCHNS ON D2 AND SHOULD REACH THE VA/DELMARVA COAST AROUND 12Z TUE. A N-S GRADIENT OF PWS WILL EXIST OVER THE AREA WITH THE BEST MSTR /1.5+ INCH PWATS/ POOLING FROM SRN PA SWD INTO THE SRN MID ATLANTIC AND SOUTHEAST STATES. WAA/ISENT LIFT ALONG WITH INCR ESELY LLVL INFLOW SHOULD BRING RAIN INTO AT LEAST THE SRN PARTS OF THE REGION WITH GLOBAL MODELS AND ENSEMBLE DATA DEPICTING THE HIGHEST QPF AMTS OVER NRN VA BLUE RIDGE/WV PNHDL/XTRME S-CNTRL PA. THERE IS A LARGE SPREAD IN THE GUIDANCE CONCERNING THE EVOLUTION OF THE LOW AS IT MOVES OFFSHORE BY 12Z WED. MEANWHILE...THE NEXT H5 S/WV TROUGH STARTS TO CROSS THE GRT LKS REGION WITH AN ACCOMPANYING SFC LOW OF ITS OWN REACHING LK MI VCNTY BY THE END OF THE PERIOD. THIS FRONTAL SYSTEM SHOULD BRING RAIN INTO THE AREA THRU MID-WEEK. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OFF WITH A WEAK SFC LOW AND ASSOCD FRONTAL SYSTEM TRACKING EWD THRU THE GRT LKS WED-FRI. THIS WILL KEEP THE PATTERN UNSETTLED AND POTENTIALLY WET DURING THE SECOND HALF OF THE WORK WEEK. FOR NOW IT APPEARS A DRYING TREND WILL START THE WEEKEND WITH HIGH PRESSURE TAKING UP RESIDENCE IN NRN NEW ENGLAND. BLOCKING OVER ATLANTIC CANADA AND GREENLAND SHOULD ALLOW FOR THE BERMUDA HIGH AND SOUTHEAST RIDGE TO BUILD WWD INTO THE TN AND LWR MS VLYS...WHILE EASTERLY COMPNT TO THE LLVL FLOW TEMPERS HIGHS DESPITE RISING HGTS ALOFT. A CONSENSUS BLEND OF WPC WITH GFS AND ECMWF MOS BASED PRODUCTS FAVORS NEAR OR JUST BLW CLIMO NUMBERS FOR MID-LATE AUGUST. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... A WEAKENING COLD FRONT WILL PUSH SE ACROSS THE AREA OVERNIGHT... ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF PRE-DAWN LOW CIGS AT KBFD...CAUSED BY POST-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA AND MOISTENING CAUSED BY SHOWERS NOW OCCURRING. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z- 14Z TIME FRAME. FARTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIGNIFICANT RESTRICTIONS MUCH LESS LIKELY. THE COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING THE DAY TODAY. ANY LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION. OUTLOOK... MON...AM FOG POSS N MTNS. SLIGHT CHC OF PM TSRA IMPACTS KJST/KAOO. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED-THU...AM FOG POSS. SCT PM TSRA IMPACTS POSS W MTNS...ESP W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
808 PM MDT MON AUG 18 2014 .UPDATE... ISSUED AT 806 PM MDT MON AUG 18 2014 00Z KUNR SOUNDING SHOWED A BIT OF MUCAPE. COUPLE OF WEAK SHORTWAVES OVER SOUTH CENTRAL MT/NORTHWEST WY WILL MOVE EAST THROUGH THE SOUTHWEST THIRD OF THE CWA OVERNIGHT BRINGING WITH IT ISOLATED TSRA. LATEST HRRR SEEMS TO PICK UP ON THIS AS WELL AS CURRENT RADAR TRENDS TO OUR WEST. WILL SPREAD POPS FROM CURRENT RADAR RETURNS THROUGH SOUTHWEST THIRD OF CWA TO ACCOUNT WITH UPDATE. && .SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT ISSUED AT 300 PM MDT MON AUG 18 2014 CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHERN MN WITH HIGH PRESSURE OVER CENTRAL MT. UPPER LEVEL ANALYSIS SHOWS TROF OVER SOUTH CENTRAL CANADA...WITH NORTHWESTERLY FLOW OVER MOST OF THE NORTHERN HIGH PLAINS. DRIER AIR IS IN PLACE ACROSS THE AREA FOR TODAY...WITH DEWPOINTS MOSTLY IN THE UPPER 40S AND 50S. SHOWERS AND STORMS THIS AFTERNOON HAVE STAYED TO THE NORTH AND SOUTH OF THE CWA...WITH A FEW STRONG STORMS OVER THE NEB PANHANDLE RIGHT NOW. TEMPS ARE IN THE UPPER 79S TO UPPER 80S WITH BRISK NORTHWESTERLY WINDS ACROSS MUCH OF THE PLAINS. THESE WINDS WILL BEGIN TO DIMINISH BY EARLY EVENING. UNSETTLED WEATHER WILL RETURN LATER ON TUESDAY AND PERSIST AT TIMES THROUGH THE END OF THE WEEK AS HIGH PRESSURE ALOFT MOVES INTO THE SOUTHEASTERN CONUS AND A BROAD TROF DEVELOPS OVER THE WESTERN STATES. DAILY CHANCES FOR SHOWERS AND STORMS CAN BE EXPECTED... ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. FOR TONIGHT...SKIES WILL BE CLEAR TO PARTLY CLOUDY. A WEAK DISTURBANCE IN NORTHWEST FLOW COULD PRODUCE A FEW SHOWERS AND POSSIBLY A STORM LATE TONIGHT INTO EARLY TUESDAY OVER THE BLACK HILLS AREA. WINDS WILL BECOME LIGHT THIS EVENING AND THEN SWITCH TO THE SOUTHEAST OVERNIGHT INTO TUESDAY MORNING AS HIGH PRESSURE PASSES OVER AND EVENTUALLY EAST OF THE AREA. WARMER AIR WILL RETURN ON TUESDAY AS SOUTH-SOUTHEAST WINDS INCREASE. HIGHS WILL BE IN THE MID 80S TO AROUND 90 DEGREES ACROSS THE PLAINS...MOSTLY 80S OVER THE BLACK HILLS. A MORE WIDESPREAD CHANCE FOR STORMS WILL RETURN LATE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS FLOW ALOFT TURNS SOUTHWESTERLY OVER THE HIGH PLAINS. THE SOUTH-SOUTHEAST WINDS WILL ALSO BRING LOW LEVEL MOISTURE BACK INTO THE AREA...WITH INCREASING INSTABILITY INTO TUESDAY NIGHT. WILL GENERALLY KEEP POPS AS IS LATE TUESDAY INTO TUESDAY NIGHT. THE THREAT FOR SEVERE STORMS STILL LOOKS RELATIVELY LOW. HOWEVER...WITH SUFFICIENT INSTABILITY AROUND...ISOLATED STRONG TO MARGINALLY SEVERE STORMS WITH HAIL AND GUSTY WINDS ARE CERTAINLY POSSIBLE LATE IN THE AFTERNOON INTO THE EVENING. && .LONG TERM...WEDNESDAY THROUGH MONDAY ISSUED AT 300 PM MDT MON AUG 18 2014 MEAN WESTERN NOAM TROUGHING WILL PERSIST IN THE PERIOD...WITH MASSIVE EASTERN NOAM RIDGING ENSUING TOWARD THE END OF THE WEEK. THIS WILL SUPPORT A LOCAL PATTERN CHANGE AS LOWER HEIGHTS AND MUCH COOLER TEMPS SPREAD OVER THE NORTHERN PLAINS BY THIS WEEKEND...PER THE WESTERN CONUS TROUGH PHASING WITH A LONG WAVE NORTHERN STREAM TROUGH. ACTIVE SW FLOW CAN BE EXPECTED TO SUPPORT NEAR DAILY CHANCES FOR PRECIP THROUGH THE PERIOD...WITH THE WESTERN CONUS TROUGH SHIFTING EAST OVER THE NORTHERN PLAINS BY LATE THIS WEEKEND. HAVE RETAINED DAILY CHANCES FOR SHRA/TS WITH A WAVERING FRONTAL ZONE OVER THE REGION THROUGH THUR. COLD FRONT WILL SHIFT SE TROUGH THE REGION FRIDAY...WITH CAA SPREADING ACROSS THE REGION VIA GUSTY NW WINDS. CYCLONIC DISTURBED SW FLOW WILL PERSIST THROUGH THE WEEKEND. HOWEVER...GIVEN SIGNALS FOR THE BEST LSA BEING NW OF THE FA...WITH MORE DIURNALLY DRIVEN CHANCES FOR CONVECTION...HAVE BIASED POPS MORE TOWARD CLIMO NUMBERS THIS WEEKEND..ESP GIVEN CONVECTIVE NATURE TO PRECIP. AS FOR TEMPS...SEASONAL NUMBERS WILL PERSIST THROUGH THURS...WITH COOLING CONDITIONS FRI-SUN. TEMPERATURES ARE PROGGED TO BE 5 TO 15 DEGREES BELOW SEASONAL NORMS BY SUNDAY AND MONDAY...ESP HIGH TEMPERATURES. HAVE CONTINUED TO ADD A NEGATIVE BIAS PER HIGHS SAT-MONDAY...WITH MANY PLACES LIKELY STRUGGLING TO REACH 70 ACROSS THE NORTHERN HALF SUNDAY AND MONDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 518 PM MDT MON AUG 18 2014 VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. A WARM FRONT WILL SHIFT NORTH TONIGHT AND POSSIBLY SUPPORT AN ISOLATED TSRA LATE TONIGHT. ADDITIONAL ACTIVITY IS POSSIBLE LATER TUESDAY AFTERNOON. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...HELGESON SHORT TERM...26 LONG TERM...JC AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1208 PM CDT SUN AUG 17 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CDT SUN AUG 17 2014 A MAJORITY OF THE PRECIPITATION THIS MORNING HAS REMAINED NORTH OF THE CWA CLOSER TO THE MID LEVEL VORTICITY MAXIMUM. ALL THE HI RES MODELS ARE OVERDOING PRECIPITATION OVER OUR AREA...POSSIBLY DUE TO DRY AIR ABOVE 600 MB AS SEEN ON RAP SOUNDINGS. DO THINK THEY HAVE THE GENERAL IDEA OF WHERE THE THUNDERSTORM THREAT IS THOUGH...AHEAD OF THE EASTWARD MOVING SURFACE AND UPPER TROUGH AXIS. BASED ON WHAT HAPPENED YESTERDAY AND SO FAR TONIGHT...WILL LEAN TOWARDS JUST AN ISOLATED TO WIDELY SCATTERED SHOWER AND THUNDERSTORM THREAT TODAY...MAINLY ACROSS SOUTHWEST MINNESOTA AND ADJACENT AREAS OF NORTHWEST IOWA. THE REST OF US WILL BE IN A SUBSIDENT REGIME ALOFT BEHIND THE WAVE...WHICH SHOULD SUPPRESS CONVECTIVE DEVELOPMENT. PATCHY AREAS OF DENSE FOG THIS MORNING NEAR THE SURFACE TROUGH SHOULD DISSIPATE AFTER SUNRISE. MAY SEE SOME STRATOCU DEVELOPMENT THIS MORNING GIVEN THE MOIST LOW LEVELS...HOWEVER THIS SHOULD SCATTER OUT BY LATER THIS MORNING AS WE BEGIN MIXING. GIVEN YESTERDAYS HIGH TEMPERATURES....AND THE FACT THAT TODAY SHOULD SEE JUST AS MUCH IF NOT MORE SUN AND WARMER TEMPERATURES ALOFT...WENT AHEAD AND BUMPED HIGHS UP A COUPLE DEGREES...MAINLY INTO THE LOW TO MID 80S. WITH DEWPOINTS RUNNING IN THE UPPER 60S TO LOW 70S AND LIGHT WINDS IT WILL FEEL QUITE WARM AND HUMID OUTSIDE. OTHER FORECAST CONCERN IS CONVECTION CHANCES LATER TODAY INTO TONIGHT AS ANOTHER WAVE MOVES ACROSS THE PLAINS. CONVECTION WILL LIKELY FORM THIS AFTERNOON IN THE WESTERN PLAINS AND MOVE TOWARDS OUR AREA THIS EVENING. STILL DECENT UNCERTAINTY ON HOW EXACTLY THE EVOLUTION OF THINGS WILL PLAY OUT...BUT SEEMS LIKE A GOOD CHANCE FOR PRECIPITATION OVER MOST OF OUR AREA. GIVEN THE LOSS OF DAYTIME HEATING STORMS WILL PROBABLY BE IN A WEAKENING STATE AS THEY APPROACH THE WESTERN EDGE OF OUR CWA AFTER 0Z. HOWEVER THE LOW LEVEL JET WILL INCREASE ACROSS NEBRASKA AFTER SUNSET...PUTTING OUR CWA IN A GOOD AREA OF LOW LEVEL CONVERGENCE ON THE NOSE OF THE JET. WOULD SEEM LIKE THIS COMBINED WITH THE UPPER SUPPORT FROM THE VORT MAX MOVING ACROSS THE CWA SHOULD BE ENOUGH TO EITHER SUSTAIN THE STORMS...OR ALLOW REDEVELOPMENT OVERHEAD THROUGH THE NIGHT. THIS IS SUPPORTED BY A MAJORITY OF THE GLOBAL MODELS. HOWEVER THE HI RES MODELS ARE LESS AGGRESSIVE AS THEY HAVE MORE CONVECTION DIVING SOUTHEAST INTO NEBRASKA THIS AFTERNOON AND EVENING...POSSIBLY IMPACTING THE MOISTURE FLOW INTO OUR AREA. SO WHILE THE FORCING SEEMS TO SUGGEST A GOOD THUNDERSTORM THREAT TONIGHT...NOTHING IS A SURE BET WITH CONVECTION...SO WILL NEED TO MONITOR TRENDS. EITHER WAY LOW END LIKELY POPS SEEM WARRANTED. A SEVERE THREAT MAY EXIST IN OUR FAR WEST THIS EVENING WITH THE OUTFLOW DOMINANT CONVECTION MOVING IN FROM THE WEST POSSIBLY POSING A WIND RISK. HOWEVER...WOULD EXPECT THIS THREAT TO WANE OVERNIGHT AS CONVECTION PUSHES EAST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 332 AM CDT SUN AUG 17 2014 SCATTERED CONVECTION WILL LIKELY BE ONGOING BY DAYBREAK MONDAY AS SHORTWAVE ENERGY AT THE BASE OF A DEEPENING TROUGH MOVES THROUGH THE REGION. THIS CONVECTION WILL MOVE EAST OF THE AREA BY MID- MORNING...WITH A BRIEF LULL BEFORE AXIS OF LARGER SYNOPTIC TROUGH PIVOTS THROUGH THE REGION LATER IN THE DAY. FRONTAL BOUNDARY BRINGING SLIGHTLY DRIER AIR SOUTHWARD WILL RACE THROUGH THE CWA EARLY MONDAY AFTERNOON...AND IT`S POSSIBLE TO HAVE REDEVELOPMENT ALONG THIS BOUNDARY AS SUGGESTED BY SEVERAL HIGH-RES MODEL SOLUTIONS. QUESTIONS LINGER ON THE AMOUNT OF DESTABILIZATION AFTER MORNING CONVECTION. ADDITIONALLY SHEAR REMAINS FAIRLY UNIDIRECTIONAL WITH SPEEDS INCREASING AFTER THE FRONT PASSES. THAT SAID...IF THINGS LINE UP JUST RIGHT...COULD SEE A VERY BRIEF WINDOW FOR A FEW STRONGER STORMS OVER THE SERN THIRD OF THE CWA MONDAY AFTN. SLIGHTLY DRIER AIR WILL FILTER INTO THE AREA FOR MONDAY NIGHT AND TUESDAY...BUT MORE HUMID AIR WON`T BE FAR TO THE SOUTH. MODELS CONVERGING ONTO A SOLN THAT SUGGEST A MORE FLATTENED MID-LEVEL RIDGE THROUGH MIDWEEK...BEFORE THE LONGWAVE PATTERN AMPLIFIES BY NEXT WEEKEND. SEVERAL SHORTWAVES WILL LIFT NE THROUGH THE MID-LVL FLOW...LIKELY BRINGING A CHANCE FOR CONVECTION SOUTH OF THE CWA WEDNESDAY...WITH MUCH MORE UNCERTAINTY ON RAIN CHANCES LIFTING NORTHWARD ON THURSDAY. THE PATTERN INTO NEXT WEEKEND WOULD FAVOR TWO THINGS...ABOVE NORMAL TEMPERATURES AND INCREASED PRECIPITATION CHANCES...ESPECIALLY FRIDAY INTO SATURDAY AS SOUTHWEST FLOW INCREASES AND AN UPPER LVL JET NOSES INTO THE PLAINS. QUESTIONS REMAIN HOWEVER ON JUST HOW THE UPPER TROUGH OVER THE PACIFIC NW WILL EVOLVE...AND WHERE ENERGY OFF THE CALIFORNIA COAST WILL END UP. NEVERTHELESS...A FORECAST PERIOD TO KEEP AN EYE ON. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1203 PM CDT SUN AUG 17 2014 STRATUS ACROSS PORTIONS OF THE AREA WILL CONTINUE TO BREAK UP THROUGH THE AFTERNOON. OTHERWISE...THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER CENTRAL SOUTH DAKOTA THIS AFTERNOON AND PUSH EASTWARD DURING THE OVERNIGHT HOURS...EFFECTING AREAS TO THE WEST OF INTERSTATE 29 GENERALLY PRIOR TO 06Z...THEN AREAS TO THE EAST LATER IN THE NIGHT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...DUX AVIATION...JM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
652 AM CDT SUN AUG 17 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CDT SUN AUG 17 2014 A MAJORITY OF THE PRECIPITATION THIS MORNING HAS REMAINED NORTH OF THE CWA CLOSER TO THE MID LEVEL VORTICITY MAXIMUM. ALL THE HI RES MODELS ARE OVERDOING PRECIPITATION OVER OUR AREA...POSSIBLY DUE TO DRY AIR ABOVE 600 MB AS SEEN ON RAP SOUNDINGS. DO THINK THEY HAVE THE GENERAL IDEA OF WHERE THE THUNDERSTORM THREAT IS THOUGH...AHEAD OF THE EASTWARD MOVING SURFACE AND UPPER TROUGH AXIS. BASED ON WHAT HAPPENED YESTERDAY AND SO FAR TONIGHT...WILL LEAN TOWARDS JUST AN ISOLATED TO WIDELY SCATTERED SHOWER AND THUNDERSTORM THREAT TODAY...MAINLY ACROSS SOUTHWEST MINNESOTA AND ADJACENT AREAS OF NORTHWEST IOWA. THE REST OF US WILL BE IN A SUBSIDENT REGIME ALOFT BEHIND THE WAVE...WHICH SHOULD SUPPRESS CONVECTIVE DEVELOPMENT. PATCHY AREAS OF DENSE FOG THIS MORNING NEAR THE SURFACE TROUGH SHOULD DISSIPATE AFTER SUNRISE. MAY SEE SOME STRATOCU DEVELOPMENT THIS MORNING GIVEN THE MOIST LOW LEVELS...HOWEVER THIS SHOULD SCATTER OUT BY LATER THIS MORNING AS WE BEGIN MIXING. GIVEN YESTERDAYS HIGH TEMPERATURES....AND THE FACT THAT TODAY SHOULD SEE JUST AS MUCH IF NOT MORE SUN AND WARMER TEMPERATURES ALOFT...WENT AHEAD AND BUMPED HIGHS UP A COUPLE DEGREES...MAINLY INTO THE LOW TO MID 80S. WITH DEWPOINTS RUNNING IN THE UPPER 60S TO LOW 70S AND LIGHT WINDS IT WILL FEEL QUITE WARM AND HUMID OUTSIDE. OTHER FORECAST CONCERN IS CONVECTION CHANCES LATER TODAY INTO TONIGHT AS ANOTHER WAVE MOVES ACROSS THE PLAINS. CONVECTION WILL LIKELY FORM THIS AFTERNOON IN THE WESTERN PLAINS AND MOVE TOWARDS OUR AREA THIS EVENING. STILL DECENT UNCERTAINTY ON HOW EXACTLY THE EVOLUTION OF THINGS WILL PLAY OUT...BUT SEEMS LIKE A GOOD CHANCE FOR PRECIPITATION OVER MOST OF OUR AREA. GIVEN THE LOSS OF DAYTIME HEATING STORMS WILL PROBABLY BE IN A WEAKENING STATE AS THEY APPROACH THE WESTERN EDGE OF OUR CWA AFTER 0Z. HOWEVER THE LOW LEVEL JET WILL INCREASE ACROSS NEBRASKA AFTER SUNSET...PUTTING OUR CWA IN A GOOD AREA OF LOW LEVEL CONVERGENCE ON THE NOSE OF THE JET. WOULD SEEM LIKE THIS COMBINED WITH THE UPPER SUPPORT FROM THE VORT MAX MOVING ACROSS THE CWA SHOULD BE ENOUGH TO EITHER SUSTAIN THE STORMS...OR ALLOW REDEVELOPMENT OVERHEAD THROUGH THE NIGHT. THIS IS SUPPORTED BY A MAJORITY OF THE GLOBAL MODELS. HOWEVER THE HI RES MODELS ARE LESS AGGRESSIVE AS THEY HAVE MORE CONVECTION DIVING SOUTHEAST INTO NEBRASKA THIS AFTERNOON AND EVENING...POSSIBLY IMPACTING THE MOISTURE FLOW INTO OUR AREA. SO WHILE THE FORCING SEEMS TO SUGGEST A GOOD THUNDERSTORM THREAT TONIGHT...NOTHING IS A SURE BET WITH CONVECTION...SO WILL NEED TO MONITOR TRENDS. EITHER WAY LOW END LIKELY POPS SEEM WARRANTED. A SEVERE THREAT MAY EXIST IN OUR FAR WEST THIS EVENING WITH THE OUTFLOW DOMINANT CONVECTION MOVING IN FROM THE WEST POSSIBLY POSING A WIND RISK. HOWEVER...WOULD EXPECT THIS THREAT TO WANE OVERNIGHT AS CONVECTION PUSHES EAST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 332 AM CDT SUN AUG 17 2014 SCATTERED CONVECTION WILL LIKELY BE ONGOING BY DAYBREAK MONDAY AS SHORTWAVE ENERGY AT THE BASE OF A DEEPENING TROUGH MOVES THROUGH THE REGION. THIS CONVECTION WILL MOVE EAST OF THE AREA BY MID- MORNING...WITH A BRIEF LULL BEFORE AXIS OF LARGER SYNOPTIC TROUGH PIVOTS THROUGH THE REGION LATER IN THE DAY. FRONTAL BOUNDARY BRINGING SLIGHTLY DRIER AIR SOUTHWARD WILL RACE THROUGH THE CWA EARLY MONDAY AFTERNOON...AND IT`S POSSIBLE TO HAVE REDEVELOPMENT ALONG THIS BOUNDARY AS SUGGESTED BY SEVERAL HIGH-RES MODEL SOLUTIONS. QUESTIONS LINGER ON THE AMOUNT OF DESTABILIZATION AFTER MORNING CONVECTION. ADDITIONALLY SHEAR REMAINS FAIRLY UNIDIRECTIONAL WITH SPEEDS INCREASING AFTER THE FRONT PASSES. THAT SAID...IF THINGS LINE UP JUST RIGHT...COULD SEE A VERY BRIEF WINDOW FOR A FEW STRONGER STORMS OVER THE SERN THIRD OF THE CWA MONDAY AFTN. SLIGHTLY DRIER AIR WILL FILTER INTO THE AREA FOR MONDAY NIGHT AND TUESDAY...BUT MORE HUMID AIR WON`T BE FAR TO THE SOUTH. MODELS CONVERGING ONTO A SOLN THAT SUGGEST A MORE FLATTENED MID-LEVEL RIDGE THROUGH MIDWEEK...BEFORE THE LONGWAVE PATTERN AMPLIFIES BY NEXT WEEKEND. SEVERAL SHORTWAVES WILL LIFT NE THROUGH THE MID-LVL FLOW...LIKELY BRINGING A CHANCE FOR CONVECTION SOUTH OF THE CWA WEDNESDAY...WITH MUCH MORE UNCERTAINTY ON RAIN CHANCES LIFTING NORTHWARD ON THURSDAY. THE PATTERN INTO NEXT WEEKEND WOULD FAVOR TWO THINGS...ABOVE NORMAL TEMPERATURES AND INCREASED PRECIPITATION CHANCES...ESPECIALLY FRIDAY INTO SATURDAY AS SOUTHWEST FLOW INCREASES AND AN UPPER LVL JET NOSES INTO THE PLAINS. QUESTIONS REMAIN HOWEVER ON JUST HOW THE UPPER TROUGH OVER THE PACIFIC NW WILL EVOLVE...AND WHERE ENERGY OFF THE CALIFORNIA COAST WILL END UP. NEVERTHELESS...A FORECAST PERIOD TO KEEP AN EYE ON. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 646 AM CDT SUN AUG 17 2014 SURFACE TROUGH ALMOST TO INTERSTATE 29 THIS MORNING. AREA OF IFR TO LIFR STRATUS HAS DEVELOPED ALONG AND BEHIND THIS TROUGH. WITH DAYTIME HEATING...SHOULD SEE STRATOCU FIELD INCREASE GIVEN THE MOIST LOW LEVELS. THIS STRATOCU WILL SLOWLY LIFT AND SCATTER OUT AS WE HEAD THROUGH THE MORNING INTO THE AFTERNOON. EXACT TIMING OF THIS RETURN TO VFR REMAINS UNCERTAIN. SHOWER AND THUNDERSTORM THREAT WILL INCREASE FROM WEST TO EAST ACROSS THE AREA TONIGHT. HOWEVER STILL TOO FAR OUT TO NARROW DOWN TIMING...SO WILL LEAVE OUT OF THE TAFS FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...DUX AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
405 AM CDT SUN AUG 17 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CDT SUN AUG 17 2014 A MAJORITY OF THE PRECIPITATION THIS MORNING HAS REMAINED NORTH OF THE CWA CLOSER TO THE MID LEVEL VORTICITY MAXIMUM. ALL THE HI RES MODELS ARE OVERDOING PRECIPITATION OVER OUR AREA...POSSIBLY DUE TO DRY AIR ABOVE 600 MB AS SEEN ON RAP SOUNDINGS. DO THINK THEY HAVE THE GENERAL IDEA OF WHERE THE THUNDERSTORM THREAT IS THOUGH...AHEAD OF THE EASTWARD MOVING SURFACE AND UPPER TROUGH AXIS. BASED ON WHAT HAPPENED YESTERDAY AND SO FAR TONIGHT...WILL LEAN TOWARDS JUST AN ISOLATED TO WIDELY SCATTERED SHOWER AND THUNDERSTORM THREAT TODAY...MAINLY ACROSS SOUTHWEST MINNESOTA AND ADJACENT AREAS OF NORTHWEST IOWA. THE REST OF US WILL BE IN A SUBSIDENT REGIME ALOFT BEHIND THE WAVE...WHICH SHOULD SUPPRESS CONVECTIVE DEVELOPMENT. PATCHY AREAS OF DENSE FOG THIS MORNING NEAR THE SURFACE TROUGH SHOULD DISSIPATE AFTER SUNRISE. MAY SEE SOME STRATOCU DEVELOPMENT THIS MORNING GIVEN THE MOIST LOW LEVELS...HOWEVER THIS SHOULD SCATTER OUT BY LATER THIS MORNING AS WE BEGIN MIXING. GIVEN YESTERDAYS HIGH TEMPERATURES....AND THE FACT THAT TODAY SHOULD SEE JUST AS MUCH IF NOT MORE SUN AND WARMER TEMPERATURES ALOFT...WENT AHEAD AND BUMPED HIGHS UP A COUPLE DEGREES...MAINLY INTO THE LOW TO MID 80S. WITH DEWPOINTS RUNNING IN THE UPPER 60S TO LOW 70S AND LIGHT WINDS IT WILL FEEL QUITE WARM AND HUMID OUTSIDE. OTHER FORECAST CONCERN IS CONVECTION CHANCES LATER TODAY INTO TONIGHT AS ANOTHER WAVE MOVES ACROSS THE PLAINS. CONVECTION WILL LIKELY FORM THIS AFTERNOON IN THE WESTERN PLAINS AND MOVE TOWARDS OUR AREA THIS EVENING. STILL DECENT UNCERTAINTY ON HOW EXACTLY THE EVOLUTION OF THINGS WILL PLAY OUT...BUT SEEMS LIKE A GOOD CHANCE FOR PRECIPITATION OVER MOST OF OUR AREA. GIVEN THE LOSS OF DAYTIME HEATING STORMS WILL PROBABLY BE IN A WEAKENING STATE AS THEY APPROACH THE WESTERN EDGE OF OUR CWA AFTER 0Z. HOWEVER THE LOW LEVEL JET WILL INCREASE ACROSS NEBRASKA AFTER SUNSET...PUTTING OUR CWA IN A GOOD AREA OF LOW LEVEL CONVERGENCE ON THE NOSE OF THE JET. WOULD SEEM LIKE THIS COMBINED WITH THE UPPER SUPPORT FROM THE VORT MAX MOVING ACROSS THE CWA SHOULD BE ENOUGH TO EITHER SUSTAIN THE STORMS...OR ALLOW REDEVELOPMENT OVERHEAD THROUGH THE NIGHT. THIS IS SUPPORTED BY A MAJORITY OF THE GLOBAL MODELS. HOWEVER THE HI RES MODELS ARE LESS AGGRESSIVE AS THEY HAVE MORE CONVECTION DIVING SOUTHEAST INTO NEBRASKA THIS AFTERNOON AND EVENING...POSSIBLY IMPACTING THE MOISTURE FLOW INTO OUR AREA. SO WHILE THE FORCING SEEMS TO SUGGEST A GOOD THUNDERSTORM THREAT TONIGHT...NOTHING IS A SURE BET WITH CONVECTION...SO WILL NEED TO MONITOR TRENDS. EITHER WAY LOW END LIKELY POPS SEEM WARRANTED. A SEVERE THREAT MAY EXIST IN OUR FAR WEST THIS EVENING WITH THE OUTFLOW DOMINANT CONVECTION MOVING IN FROM THE WEST POSSIBLY POSING A WIND RISK. HOWEVER...WOULD EXPECT THIS THREAT TO WANE OVERNIGHT AS CONVECTION PUSHES EAST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 332 AM CDT SUN AUG 17 2014 SCATTERED CONVECTION WILL LIKELY BE ONGOING BY DAYBREAK MONDAY AS SHORTWAVE ENERGY AT THE BASE OF A DEEPENING TROUGH MOVES THROUGH THE REGION. THIS CONVECTION WILL MOVE EAST OF THE AREA BY MID- MORNING...WITH A BRIEF LULL BEFORE AXIS OF LARGER SYNOPTIC TROUGH PIVOTS THROUGH THE REGION LATER IN THE DAY. FRONTAL BOUNDARY BRINGING SLIGHTLY DRIER AIR SOUTHWARD WILL RACE THROUGH THE CWA EARLY MONDAY AFTERNOON...AND IT`S POSSIBLE TO HAVE REDEVELOPMENT ALONG THIS BOUNDARY AS SUGGESTED BY SEVERAL HIGH-RES MODEL SOLUTIONS. QUESTIONS LINGER ON THE AMOUNT OF DESTABILIZATION AFTER MORNING CONVECTION. ADDITIONALLY SHEAR REMAINS FAIRLY UNIDIRECTIONAL WITH SPEEDS INCREASING AFTER THE FRONT PASSES. THAT SAID...IF THINGS LINE UP JUST RIGHT...COULD SEE A VERY BRIEF WINDOW FOR A FEW STRONGER STORMS OVER THE SERN THIRD OF THE CWA MONDAY AFTN. SLIGHTLY DRIER AIR WILL FILTER INTO THE AREA FOR MONDAY NIGHT AND TUESDAY...BUT MORE HUMID AIR WON`T BE FAR TO THE SOUTH. MODELS CONVERGING ONTO A SOLN THAT SUGGEST A MORE FLATTENED MID-LEVEL RIDGE THROUGH MIDWEEK...BEFORE THE LONGWAVE PATTERN AMPLIFIES BY NEXT WEEKEND. SEVERAL SHORTWAVES WILL LIFT NE THROUGH THE MID-LVL FLOW...LIKELY BRINGING A CHANCE FOR CONVECTION SOUTH OF THE CWA WEDNESDAY...WITH MUCH MORE UNCERTAINTY ON RAIN CHANCES LIFTING NORTHWARD ON THURSDAY. THE PATTERN INTO NEXT WEEKEND WOULD FAVOR TWO THINGS...ABOVE NORMAL TEMPERATURES AND INCREASED PRECIPITATION CHANCES...ESPECIALLY FRIDAY INTO SATURDAY AS SOUTHWEST FLOW INCREASES AND AN UPPER LVL JET NOSES INTO THE PLAINS. QUESTIONS REMAIN HOWEVER ON JUST HOW THE UPPER TROUGH OVER THE PACIFIC NW WILL EVOLVE...AND WHERE ENERGY OFF THE CALIFORNIA COAST WILL END UP. NEVERTHELESS...A FORECAST PERIOD TO KEEP AN EYE ON. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1038 PM CDT SAT AUG 16 2014 HI RES MODELS CONTINUE TO DEVELOP FOG OVERNIGHT...LIKELY A RESULT OF THE CONVECTION THAT THE MODEL IS DEVELOPING THAT IS NOT THERE. WITH DECENT MIXING TODAY..HAVE CONTINUED TO CUT BACK ON FOG MENTION FOR SUNDAY MORNING. OTHERWISE...MAINLY VFR CONDITION WITH WEAK BOUNDARY IN THE JAMES VALLEY POTENTIALLY BECOMING THE FOCUS FOR ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT SUNDAY AFTERNOON. TIMING IS LOW...SO HAVE LEFT MENTION OUT OF TAFS FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...DUX AVIATION...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
921 PM CDT MON AUG 18 2014 .UPDATE... A CLUSTER OF SHOWERS AND THUNDERSTORMS ARE SKIRTING PHILLIPS COUNTY ARKANSAS AND COAHOMA COUNTY MISSISSIPPI AT THIS TIME. LATEST HRRR SHOWS THAT THE AREA FROM COAHOMA COUNTY TO MONROE COUNTY MISSISSIPPI COULD CONTINUE SEE THIS ACTIVITY INTO THE OVERNIGHT HOURS. OTHERWISE...EXPECT MAINLY DRY CONDITIONS. WILL ADJUST POPS OTHERWISE REST OF THE FORECAST LOOKS GOOD. KRM && .DISCUSSION... /ISSUED 253 PM CDT MON AUG 18 2014/ SKIES ARE PARTLY CLOUDY OVER MUCH OF THE FORECAST AREA THIS AFTERNOON WITH TEMPERATURES RANGING FROM THE LOWER 70S TO MID 80S. SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO MOVE ACROSS PORTIONS OF THE FORECAST AREA. EARLIER THIS AFTERNOON WE HAD SOME HEAVY RAINFALL OVER PORTIONS OF WEST TENNESSEE WITH 3 TO 5 INCHES OF RAIN FALLING IN A FEW LOCATIONS. THE UPPER LEVEL DISTURBANCE WHICH HELPED PRODUCE ALL THE THUNDERSTORM ACTIVITY WAS MOVING ACROSS NORTH MISSISSIPPI THIS AFTERNOON. AS THIS DISTURBANCE CONTINUES TO MOVE EAST INTO NORTH ALABAMA...THUNDERSTORMS WILL DECREASE IN COVERAGE TONIGHT. MEANWHILE...A WEAK FRONTAL BOUNDARY WAS LOCATED JUST NORTH OF THE FORECAST AREA. AS IT BEGIN TO MOVE NORTH TONIGHT...SOME ADDITIONAL THUNDERSTORMS MAY MOVE INTO NORTHWEST SECTIONS OF THE FORECAST AREA OVERNIGHT. AS THE FRONT MOVES NORTH TUESDAY...THE CHANCE OF THUNDERSTORMS WILL BE CONFINED TO MAINLY NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA. TEMPERATURES WILL START TO BECOME QUITE WARM ON TUESDAY WITH HIGHS IN THE LOW TO MID 90S. BY WEDNESDAY...AN UPPER LEVEL RIDGE WILL START TO BUILD INTO THE SOUTHEAST AND SOUTH CENTRAL U.S. THIS WILL BRING AN EXTENDED PERIOD OF DRY WEATHER TO THE FORECAST AREA WITH NO RAIN EXPECTED FROM WEDNESDAY THROUGH NEXT MONDAY. IN ADDITIONAL...TEMPERATURES WILL BE AS HOT IF NOT HOTTER THAN WE HAVE SEEN THIS SUMMER WITH HIGH TEMPERATURES IN THE MID TO UPPER 90S FROM WEDNESDAY THROUGH NEXT MONDAY. HEAT INDEX VALUES MAY EXCEED 105 AT TIMES DURING THIS PERIOD SO THERE MAY BE A NEED FOR A HEAT ADVISORY LATER THIS WEEK. ARS && .AVIATION... SHOULD BE A QUIETER NIGHT ACROSS THE MIDSOUTH AS THE UPPER LEVEL DISTURBANCE MOVES EAST OF THE REGION. VFR CONDS EXPECTED THROUGH THE EVENING WITH PATCHY FOG DEVELOPING LATER TONIGHT. LOW CLOUDS ARE POSSIBLE AT KMKL AND KTUP THOUGH CONFIDENCE IS TOO LOW FOR A BKN DECK ATTM. UPPER RIDGE WILL START BUILDING IN ON TUESDAY AND AREAL COVERAGE OF SHRAS/TSRAS WILL BE TOO LOW TO MENTION VCTS. WINDS WILL BE LIGHT OVERNIGHT AND WSW 7-10 KTS ON TUESDAY. && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
615 PM CDT MON AUG 18 2014 .AVIATION... /00Z TAFS/ As of 6 pm, there is an area of widespread rainfall with embedded thunderstorms south of KABI and KSJT and affecting only the southern terminals. VFR conditions are expected to continue through the next 24 hours at all terminals. Isolated to scattered thunderstorms are possible through mid-evening over the southern terminal. Any thunderstorms that occur will be capable of producing variable and gusty winds. Thunderstorms are expected to occur again Tuesday morning, mainly over the southern terminals. && .PREV DISCUSSION... /ISSUED 350 PM CDT MON AUG 18 2014/ .SHORT TERM... (Tonight and Tuesday) Low confidence forecast across West Central Texas for the next 24 hours. Remnant Mesoscale Convective Vortex (MCV) continues to remain nearly stationary across Sterling County early this afternoon, and buried within a larger scale mid level shear axis stretching across much of the area. Much like we saw on Sunday, as the main morning area of showers and storms slowly winds down from Abilene to Brownwood, more scattered convection is developing along the periphery of the MCV where better heating is taking place. Biggest question in the forecast concerns tonight and Tuesday rain chances. As the low level jet intensifies towards midnight, expect to see another round of showers and storms form near the center of the MCV and along its eastern flank. MCV is definitely weaker today than it was yesterday, and should continue to slowly wind down. How strong it remains tonight, where it ends up, and what kind of storm coverage it can actually generate is highly uncertain though. Models not a lot of help, with even the TTU WRF and the HRRR models struggling in this highly mesoscale situation. At this point, will bump pops to chance for most of the area, knowing that some areas may miss out and others may see some decent rainfall. Some of this area has seen rainfall totals in the 1 to 3 inch range, so if the rain can train over these areas, than a flood threat becomes more pronounced. This will need to be monitored through tonight. 07 .LONG TERM... (Tuesday night through next Monday) A mainly dry forecast expected for the extended period. By Tuesday evening...the 500mb ridge that is currently centered near Florida will expand farther west into Texas, pushing the shear axis over the top of our CWA farther west as well. In addition, by Tuesday night, 250mph ridging will move in over the top of the region out of the southwest. These two factors point to decreasing chances of precipitation overall for the area by Tuesday night. However, we have left an area of slight chance PoPs in for Tuesday evening. The combination of the previously mentioned upper level shear axis and MCV is expected to result in additional thunderstorm activity tomorrow afternoon. And although these features are expected to be drifting to the west, there could still be lingering activity for areas mainly south and west of a Sterling City to San Angelo to Sonora line. By Wednesday, upper level ridging will be in place across our forecast area, effectively ending rain chances through the end of the forecast period, and allowing temperatures to remain warm in the mid to upper 90s for highs, and generally lower to mid 70s for lows. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 72 94 71 97 74 / 30 30 5 5 5 San Angelo 71 93 72 95 74 / 30 30 10 5 5 Junction 73 92 73 93 73 / 30 30 10 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
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AREA FORECAST DISCUSSION
NWS LA CROSSE WI
610 PM CDT MON AUG 18 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 315 PM CDT MON AUG 18 2014 FORECAST FOCUS IS ON RAIN TONIGHT AS UPPER SHORT WAVE PASSES THROUGH THE REGION WITH A WARM AND HUMID AIRMASS IN PLACE. A CLOSED LOW CUTS OFF OVER THE GREAT LAKES AS THIS WAVE ROUNDS THE BASE OF THE LONG WAVE TROUGH. WITH WEAKER IMPULSES CIRCULATING AROUND THE LOW...RAIN CHANCES LINGER INTO TUESDAY AS WELL. 19Z MESOANALYSIS SHOWS UPPER WAVE SPINNING INTO NORTHWEST MN... HEADING SOUTHEAST. PLUME OF 70+ LOW LEVEL DEWPOINTS FROM EASTERN IA UP INTO WESTERN WI AHEAD OF THE APPROACHING WAVE. ACTIVE CONVECTION ONGOING FROM WEST CENTRAL INTO NORTHEAST WI...AND NEW ACTIVITY GOING UP OVER NORTHEAST IA AND SOUTHEAST MN. ANTICIPATE SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT...WITH PERHAPS A BREAK FOR A TIME EARLY THIS EVENING AFTER THIS FIRST INITIAL BAND. PRECIPITABLE WATER SOMEWHAT ELEVATED AND WARM CLOUD DEPTH 3500+ METERS. ANY STORMS WILL BE PRODUCING HEAVY DOWNPOURS. DCAPE SUGGESTS WIND POTENTIAL AS WELL. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 315 PM CDT MON AUG 18 2014 UPPER LEVEL LOW OVER THE GREAT LAKES SHIFTS EAST ON WEDNESDAY AS UPPER RIDGING BUILDS INTO THE UPPER MIDWEST. A PATTERN SHIFT TO MORE SOUTHWEST FLOW TAKES PLACE MID-WEEK WITH A LONG WAVE TROUGH ESTABLISHING ITSELF OVER THE WESTERN CONUS. EVENTUAL RAIN CHANCES LATER THIS WEEK...AND THE DEGREE OF WARMING...ARE TIED TO HOW THE SHORT WAVE TROUGH ENERGY EJECTS NORTHEAST TOWARD OUR REGION. MEDIUM RANGE MODELS DO SHOW SOME DIFFERENCES IN TIMING OF THESE IMPULSES...SO CONFIDENCE NOT HIGH. BUT IT DOES APPEAR THE OVERALL TREND OF WARM AND HUMID CONDITIONS WILL COME TO FRUITION. IT HAS BEEN DRY LATELY...BUT THESE STORMS ONCE AGAIN LOOK TO HAVE INGREDIENTS FOR HEAVY RAIN POTENTIAL. THIS WILL HAVE TO BE MONITORED AS WE START TO ACCUMULATE SOME RAINFALL ON OUR RECENTLY DRY SOILS...WILL A FLOOD WATCH EVENTUALLY BE NECESSARY? && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 610 PM CDT MON AUG 18 2014 FIRST ROUND OF AFTERNOON CONVECTION EXPECTED TO PAST BOTH TAF SITES BY 00Z. HOWEVER...THE NEXT ROUND ALREADY TAKING SHAPE ACROSS SOUTH CENTRAL MINNESOTA AHEAD OF THE NEXT SHORT WAVE TROUGH. THE 18.21Z HRRR SEEMS TO HAVE A GOOD HANDLE ON BOTH OF THESE ROUNDS OF CONVECTION BRINGING THE NEXT ROUND THROUGH BOTH TAF SITES THIS EVENING. WILL INCLUDE A TWO HOUR TEMPO GROUP FOR THUNDER WITH MVFR CONDITIONS. ONCE THIS GOES THROUGH...IT APPEARS THE WIND SHIFT/COLD FRONT SHOULD COME THROUGH SHORTLY AFTER SWINGING THE WINDS AROUND TO THE WEST. THE 18.18Z NAM SUGGESTS THAT THERE WILL BE A DECENT WEST TO NORTHWEST WIND BETWEEN 5 AND 10 KNOTS WITH WINDS OF 15 TO 20 KNOTS JUST ABOVE THE SURFACE. WHILE THE NAM WANTS TO SATURATE THE SURFACE AND PRODUCE SOME FOG AND LOW CEILINGS...CONCERNED THAT THIS MAY BE TOO MUCH WIND FOR THE FOG TO FORM AND POSSIBLY THE CEILINGS AS WELL. FOR NOW WILL MAINTAIN SOME CONTINUITY WITH PREVIOUS FORECASTS AND SHOW PREVAILING MVFR CONDITIONS WITH THE POSSIBILITY OF IFR. ANY FOG AND LOW CEILINGS THAT DO FORM SHOULD DISSIPATE BY MID MORNING TUESDAY AS THE SURFACE WINDS INCREASE TO AROUND 10 KNOTS WITH SCATTERED TO SOME BROKEN VFR CLOUDS EXPECTED FOR THE REMAINDER OF THE DAY. && .HYDROLOGY... ISSUED AT 315 PM CDT MON AUG 18 2014 SO FAR IN AUGUST...OVERALL IT HAS BEEN QUITE DRY WITH MUCH OF THE AREA ADDED TO THE ABNORMALLY DRY CATEGORY PER THE DROUGHT MONITOR. BUT AS WE SAW LAST NIGHT...SLOW MOVING STORMS PRODUCING TORRENTIAL DOWNPOURS CAN RESULT IN SOME LOCALIZED FLOODING ISSUES. ONCE AGAIN TONIGHT...WARM CLOUD DEPTH AND ELEVATED PRECIPITABLE WATER AMOUNTS POINT TO HEAVY RAINFALL POTENTIAL. THIS TREND LOOKS TO CONTINUE THROUGH MUCH OF THE WEEK AS WELL. DRY CONDITIONS INITIALLY WILL ALLOW FOR MUCH OF THIS WATER TO BE UTILIZED BY THE SOIL AND REPLENISHING STORAGE AREAS. BUT WE WILL HAVE TO MONITOR THE RAINFALL OVER THE COMING DAYS AND PERHAPS CONSIDER THE NEED FOR A FLOOD WATCH FOR AREAS THAT SEE REPEATED RAINFALL. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...MW LONG TERM...MW AVIATION...04 HYDROLOGY...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1246 PM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1147 AM CDT SUN AUG 17 2014 SHOWERS HAVE DEVELOPED ALONG A DIFFERENTIAL HEATING BOUNDARY LATE THIS MORNING ACROSS DODGE AND MOWER COUNTIES IN SOUTHEAST MINNESOTA...AND FLOYD AND MITCHELL COUNTIES IN NORTHEAST IOWA. WHILE THE MESO MODELS ARE NOT INDICATING ANY PRECIPITATION IN THIS AREA...THE RAP DOES SHOW MODERATE TO STRONG 900 TO 800 MB FORNTOGENESIS AND THE SPC MESO PAGE HAS AROUND 1000 J/KG SURFACE BASED CAPE. THESE PARAMETERS STAY PRETTY CONSISTENT AND OVER THE SAME GENERAL AREAS THIS AFTERNOON. DUE TO THIS...THE PRECIPITATION CHANCES WERE DRAMATICALLY INCREASED THIS AFTERNOON. UPDATE ISSUED AT 911 AM CDT SUN AUG 17 2014 LAW ENFORCEMENT REPORT...OBSERVATIONS...AND WEB CAMS ARE SHOWING THAT MUCH OF THE DENSE FOG HAS LIFTED ACROSS MUCH OF NORTHEAST IOWA. DUE TO THIS...THE DENSE FOG WAS ALLOWED TO EXPIRE. WHILE CONDITIONS ARE IMPROVING...DRIVERS STILL SHOULD BE ALERT FOR AREAS OF LOW VISIBILITIES THROUGH 10 AM THIS MORNING. UPDATE ISSUED AT 437 AM CDT SUN AUG 17 2014 FOG IS BECOMING A BIGGER PROBLEM OVER NORTHEAST IOWA WITH MANY SITES DROPPING TO OR BELOW 1/4 MILE VISIBILITY. MUCH OF THIS IS A RESULT OF SKIES STILL CLEAR BECAUSE THE COOL FRONT HAS YET TO MOVE INTO THE AREA. BEHIND THE FRONT ACROSS WISCONSIN...STRATUS HAS HELPED KEEP THE FOG AT BAY. THERE HAS BEEN SOME SCATTERED CLOUDS ACROSS SOUTHEAST MN AS WELL AHEAD OF THE FRONT KEEPING FOG AT A MINIMUM THERE. SHOULD THESE CLOUDS CLEAR...THEN ITS POSSIBLE THE THICKER FOG IN NORTHEAST IOWA COULD EXPAND INTO SOUTHEAST MN. HAVE WENT AHEAD...ALONG WITH DMX AND DVN...AND ISSUED A DENSE FOG ADVISORY FOR NORTHEAST IA. EXPIRATION TIME IS SET AT 9 AM...WHEN THE WIDESPREAD NATURE OF THE DENSE FOG SHOULD BEGIN TO IMPROVE. IT MAY NOT FULLY BE IMPROVED UNTIL 10 AM...THOUGH...PER 17.07Z HRRR VISIBILITY PROGS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1246 PM CDT SUN AUG 17 2014 MODERATE TO STRONG 900 TO 800 MB FRONTOGENESIS WILL PRODUCE SHOWERS AND SCATTERED THUNDRESTORMS MAINLY WEST OF KRST THIS AFTERNOON. AS A SHORT WAVE APPROACHES THE AREA THIS AFTERNOON...THESE SHOWERS WILL MOVE INTO KRST AROUND 17.23Z AND INTO KLSE AROUND 18.08Z. AS THE LOW LEVELS MOISTEN OVERNIGHT...EXPECT AN LIFR TO IFR DECK AND IFR TO MVFR FOG TO AFFECT BOTH TAF SITES AFTER 18.08Z. THIS WILL THEN PERSIST THROUGH THE REMAINDER OF MONDAY MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BOYNE SHORT TERM...AJ LONG TERM...AJ AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1147 AM CDT SUN AUG 17 2014 SHOWERS HAVE DEVELOPED ALONG A DIFFERENTIAL HEATING BOUNDARY LATE THIS MORNING ACROSS DODGE AND MOWER COUNTIES IN SOUTHEAST MINNESOTA...AND FLOYD AND MITCHELL COUNTIES IN NORTHEAST IOWA. WHILE THE MESO MODELS ARE NOT INDICATING ANY PRECIPITATION IN THIS AREA...THE RAP DOES SHOW MODERATE TO STRONG 900 TO 800 MB FORNTOGENESIS AND THE SPC MESO PAGE HAS AROUND 1000 J/KG SURFACE BASED CAPE. THESE PARAMETERS STAY PRETTY CONSISTENT AND OVER THE SAME GENERAL AREAS THIS AFTERNOON. DUE TO THIS...THE PRECIPITATION CHANCES WERE DRAMATICALLY INCREASED THIS AFTERNOON. UPDATE ISSUED AT 911 AM CDT SUN AUG 17 2014 LAW ENFORCEMENT REPORT...OBSERVATIONS...AND WEB CAMS ARE SHOWING THAT MUCH OF THE DENSE FOG HAS LIFTED ACROSS MUCH OF NORTHEAST IOWA. DUE TO THIS...THE DENSE FOG WAS ALLOWED TO EXPIRE. WHILE CONDITIONS ARE IMPROVING...DRIVERS STILL SHOULD BE ALERT FOR AREAS OF LOW VISIBILITIES THROUGH 10 AM THIS MORNING. UPDATE ISSUED AT 437 AM CDT SUN AUG 17 2014 FOG IS BECOMING A BIGGER PROBLEM OVER NORTHEAST IOWA WITH MANY SITES DROPPING TO OR BELOW 1/4 MILE VISIBILITY. MUCH OF THIS IS A RESULT OF SKIES STILL CLEAR BECAUSE THE COOL FRONT HAS YET TO MOVE INTO THE AREA. BEHIND THE FRONT ACROSS WISCONSIN...STRATUS HAS HELPED KEEP THE FOG AT BAY. THERE HAS BEEN SOME SCATTERED CLOUDS ACROSS SOUTHEAST MN AS WELL AHEAD OF THE FRONT KEEPING FOG AT A MINIMUM THERE. SHOULD THESE CLOUDS CLEAR...THEN ITS POSSIBLE THE THICKER FOG IN NORTHEAST IOWA COULD EXPAND INTO SOUTHEAST MN. HAVE WENT AHEAD...ALONG WITH DMX AND DVN...AND ISSUED A DENSE FOG ADVISORY FOR NORTHEAST IA. EXPIRATION TIME IS SET AT 9 AM...WHEN THE WIDESPREAD NATURE OF THE DENSE FOG SHOULD BEGIN TO IMPROVE. IT MAY NOT FULLY BE IMPROVED UNTIL 10 AM...THOUGH...PER 17.07Z HRRR VISIBILITY PROGS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN AUG 17 2014 LOW STRATUS WILL PRODUCE IFR CONDITIONS AT THE TAF SITES THIS MORNING WITH CEILING RANGING FROM 900 FT AT KLSE TO 200 FT AT KRST. ALSO...AS THE STRATUS ADVECTS WESTWARD INTO KRST...IT IS LIKELY THAT KRST WILL DROP TO VLIFR IN FOG. MIXING WILL INCREASE LATER THIS MORNING AND WE SHOULD SEE CONDITIONS IMPROVE TO MVFR BY LATE MORNING AND EVENTUALLY TO VFR THIS AFTERNOON. LOW PRESSURE APPROACHES FROM THE NORTHERN PLAINS TONIGHT AND WITH THE MOIST AIRMASS OVER THE REGION WE WILL ONCE AGAIN SEE STRATUS OVER THE TAF SITES. THE PRESSURE GRADIENT TIGHTENS TONIGHT WITH SOUTH WINDS INCREASING INTO THE 6 TO 12 KT RANGE. THIS SHOULD PROMOTE MIXING AND KEEP THE VISIBILITY FROM FALLING BELOW 3SM. THE LOW STRATUS WILL BE THE MAIN CONCERN WHERE CEILINGS WILL LIKELY FALL INTO THE MVFR TO IFR CATEGORY AFTER MIDNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BOYNE SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
913 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 911 AM CDT SUN AUG 17 2014 LAW ENFORCEMENT REPORT...OBSERVATIONS...AND WEB CAMS ARE SHOWING THAT MUCH OF THE DENSE FOG HAS LIFTED ACROSS MUCH OF NORTHEAST IOWA. DUE TO THIS...THE DENSE FOG WAS ALLOWED TO EXPIRE. WHILE CONDITIONS ARE IMPROVING...DRIVERS STILL SHOULD BE ALERT FOR AREAS OF LOW VISIBILITIES THROUGH 10 AM THIS MORNING. UPDATE ISSUED AT 437 AM CDT SUN AUG 17 2014 FOG IS BECOMING A BIGGER PROBLEM OVER NORTHEAST IOWA WITH MANY SITES DROPPING TO OR BELOW 1/4 MILE VISIBILITY. MUCH OF THIS IS A RESULT OF SKIES STILL CLEAR BECAUSE THE COOL FRONT HAS YET TO MOVE INTO THE AREA. BEHIND THE FRONT ACROSS WISCONSIN...STRATUS HAS HELPED KEEP THE FOG AT BAY. THERE HAS BEEN SOME SCATTERED CLOUDS ACROSS SOUTHEAST MN AS WELL AHEAD OF THE FRONT KEEPING FOG AT A MINIMUM THERE. SHOULD THESE CLOUDS CLEAR...THEN ITS POSSIBLE THE THICKER FOG IN NORTHEAST IOWA COULD EXPAND INTO SOUTHEAST MN. HAVE WENT AHEAD...ALONG WITH DMX AND DVN...AND ISSUED A DENSE FOG ADVISORY FOR NORTHEAST IA. EXPIRATION TIME IS SET AT 9 AM...WHEN THE WIDESPREAD NATURE OF THE DENSE FOG SHOULD BEGIN TO IMPROVE. IT MAY NOT FULLY BE IMPROVED UNTIL 10 AM...THOUGH...PER 17.07Z HRRR VISIBILITY PROGS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN AUG 17 2014 LOW STRATUS WILL PRODUCE IFR CONDITIONS AT THE TAF SITES THIS MORNING WITH CEILING RANGING FROM 900 FT AT KLSE TO 200 FT AT KRST. ALSO...AS THE STRATUS ADVECTS WESTWARD INTO KRST...IT IS LIKELY THAT KRST WILL DROP TO VLIFR IN FOG. MIXING WILL INCREASE LATER THIS MORNING AND WE SHOULD SEE CONDITIONS IMPROVE TO MVFR BY LATE MORNING AND EVENTUALLY TO VFR THIS AFTERNOON. LOW PRESSURE APPROACHES FROM THE NORTHERN PLAINS TONIGHT AND WITH THE MOIST AIRMASS OVER THE REGION WE WILL ONCE AGAIN SEE STRATUS OVER THE TAF SITES. THE PRESSURE GRADIENT TIGHTENS TONIGHT WITH SOUTH WINDS INCREASING INTO THE 6 TO 12 KT RANGE. THIS SHOULD PROMOTE MIXING AND KEEP THE VISIBILITY FROM FALLING BELOW 3SM. THE LOW STRATUS WILL BE THE MAIN CONCERN WHERE CEILINGS WILL LIKELY FALL INTO THE MVFR TO IFR CATEGORY AFTER MIDNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BOYNE SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
656 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 437 AM CDT SUN AUG 17 2014 FOG IS BECOMING A BIGGER PROBLEM OVER NORTHEAST IOWA WITH MANY SITES DROPPING TO OR BELOW 1/4 MILE VISIBILITY. MUCH OF THIS IS A RESULT OF SKIES STILL CLEAR BECAUSE THE COOL FRONT HAS YET TO MOVE INTO THE AREA. BEHIND THE FRONT ACROSS WISCONSIN...STRATUS HAS HELPED KEEP THE FOG AT BAY. THERE HAS BEEN SOME SCATTERED CLOUDS ACROSS SOUTHEAST MN AS WELL AHEAD OF THE FRONT KEEPING FOG AT A MINIMUM THERE. SHOULD THESE CLOUDS CLEAR...THEN ITS POSSIBLE THE THICKER FOG IN NORTHEAST IOWA COULD EXPAND INTO SOUTHEAST MN. HAVE WENT AHEAD...ALONG WITH DMX AND DVN...AND ISSUED A DENSE FOG ADVISORY FOR NORTHEAST IA. EXPIRATION TIME IS SET AT 9 AM...WHEN THE WIDESPREAD NATURE OF THE DENSE FOG SHOULD BEGIN TO IMPROVE. IT MAY NOT FULLY BE IMPROVED UNTIL 10 AM...THOUGH...PER 17.07Z HRRR VISIBILITY PROGS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN AUG 17 2014 LOW STRATUS WILL PRODUCE IFR CONDITIONS AT THE TAF SITES THIS MORNING WITH CEILING RANGING FROM 900 FT AT KLSE TO 200 FT AT KRST. ALSO...AS THE STRATUS ADVECTS WESTWARD INTO KRST...IT IS LIKELY THAT KRST WILL DROP TO VLIFR IN FOG. MIXING WILL INCREASE LATER THIS MORNING AND WE SHOULD SEE CONDITIONS IMPROVE TO MVFR BY LATE MORNING AND EVENTUALLY TO VFR THIS AFTERNOON. LOW PRESSURE APPROACHES FROM THE NORTHERN PLAINS TONIGHT AND WITH THE MOIST AIRMASS OVER THE REGION WE WILL ONCE AGAIN SEE STRATUS OVER THE TAF SITES. THE PRESSURE GRADIENT TIGHTENS TONIGHT WITH SOUTH WINDS INCREASING INTO THE 6 TO 12 KT RANGE. THIS SHOULD PROMOTE MIXING AND KEEP THE VISIBILITY FROM FALLING BELOW 3SM. THE LOW STRATUS WILL BE THE MAIN CONCERN WHERE CEILINGS WILL LIKELY FALL INTO THE MVFR TO IFR CATEGORY AFTER MIDNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>011- 018-019-029-030. && $$ UPDATE...AJ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
437 AM CDT SUN AUG 17 2014 .UPDATE... ISSUED AT 437 AM CDT SUN AUG 17 2014 FOG IS BECOMING A BIGGER PROBLEM OVER NORTHEAST IOWA WITH MANY SITES DROPPING TO OR BELOW 1/4 MILE VISIBILITY. MUCH OF THIS IS A RESULT OF SKIES STILL CLEAR BECAUSE THE COOL FRONT HAS YET TO MOVE INTO THE AREA. BEHIND THE FRONT ACROSS WISCONSIN...STRATUS HAS HELPED KEEP THE FOG AT BAY. THERE HAS BEEN SOME SCATTERED CLOUDS ACROSS SOUTHEAST MN AS WELL AHEAD OF THE FRONT KEEPING FOG AT A MINIMUM THERE. SHOULD THESE CLOUDS CLEAR...THEN ITS POSSIBLE THE THICKER FOG IN NORTHEAST IOWA COULD EXPAND INTO SOUTHEAST MN. HAVE WENT AHEAD...ALONG WITH DMX AND DVN...AND ISSUED A DENSE FOG ADVISORY FOR NORTHEAST IA. EXPIRATION TIME IS SET AT 9 AM...WHEN THE WIDESPREAD NATURE OF THE DENSE FOG SHOULD BEGIN TO IMPROVE. IT MAY NOT FULLY BE IMPROVED UNTIL 10 AM...THOUGH...PER 17.07Z HRRR VISIBILITY PROGS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1142 PM CDT SAT AUG 16 2014 LOOKS LIKE ANOTHER GOOD NIGHT FOR THE FORMATION OF FOG AND LOW STRATUS ACROSS THE AREA. THE WEAK COLD FRONT CONTINUES TO MAKE SLOW SOUTHWARD PROGRESS AND SHOULD EVENTUALLY PASS THROUGH BOTH SITES. HOWEVER...THE WIND FIELD AHEAD OF THE FRONT IS SO LIGHT WITH ONLY A MINOR INCREASE IN SPEEDS BEHIND THE FRONT...THAT IT WILL NOT MAKE MUCH OF AN IMPACT. SOME CLOUDS CURRENTLY WITH THE FRONT...BUT GENERALLY MOSTLY CLEAR AHEAD OF IT. EXPECT TO SEE SOME FOG AND STRATUS DEVELOP BEFORE THE PASSAGE OF THE FRONT AND LOCAL WEB CAM ALREADY SHOWING SIGNS OF THIS OVER THE MISSISSIPPI RIVER CHANNEL. ONCE THE FRONT GOES THROUGH...THE 17.00Z NAM AND 17.03Z RAP BOTH SHOW SOME INCREASE IN THE LOW LEVEL WINDS OUT OF THE EAST TO THE POINT THAT SURFACE DEW POINTS MAY START TO DRY OUT SOME AT KLSE SO THAT THE VISIBILITY MAY NOT GET TOO LOW. A VISIBILITY BELOW A MILE STILL POSSIBLE AT KRST THOUGH. CONDITIONS EXPECTED TO SLOWLY IMPROVE SUNDAY MORNING WITH A RETURN TO VFR CONDITIONS BY EARLY AFTERNOON. THE NAM SUGGESTS THE POSSIBILITY OF SOME SHOWERS AND STORMS IN THE AFTERNOON AS A SHORT WAVE TROUGH COMES OUT OF THE DAKOTAS AND ACROSS MINNESOTA. HOWEVER...ITS FORECAST SOUNDINGS SHOW VERY LITTLE VERTICAL MOTION AND OPTED TO STAY WITH A DRY FORECAST. BETTER CHANCES FOR RAIN MAY COME AFTER 06Z MONDAY AS A STRONGER SHORT WAVE TROUGH APPROACHES. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>011- 018-019-029-030. && $$ UPDATE...AJ SHORT TERM...AJ LONG TERM...AJ AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 AM CDT SUN AUG 17 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 310 AM CDT SUN AUG 17 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW AND TROUGH TRAVERSING SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA...A SHORTWAVE NEAR FARGO...AND RIDGING OVER EASTERN MN. SUBSIDENCE UNDER THIS UPPER RIDGING HAS RESULTED IN MAINLY DRY CONDITIONS OVERNIGHT IN THE FORECAST AREA. THERE WERE SHOWERS LAST EVENING AROUND I-94 FROM CENTRAL MN INTO SOUTHEAST WI...ASSOCIATED WITH LINGERING DAYTIME INSTABILITY AND CONVERGENCE ALONG A BACKDOOR COLD FRONT. THOSE HAVE SINCE MOSTLY DISSIPATED DUE TO LOSS OF DAYTIME HEATING. THAT COLD FRONT NOW STRETCHES FROM SOUTHERN WI INTO SOUTHWEST MN AND TO A LOW IN SOUTHEAST NORTH DAKOTA. AROUND THIS SURFACE LOW AND THE ASSOCIATED SHORTWAVE ALOFT...MORE SHOWERS AND STORMS EXIST. GOES PRECIPITABLE WATER IMAGERY DEPICTS PLENTIFUL MOISTURE POOLED ALONG THE FRONT...WITH VALUES RANGING FROM 1.5-2 INCHES...HIGHEST IN THE CONVECTION NEAR FARGO. THE MOISTURE HAS BEEN FELT AT THE SURFACE AS WELL WITH DEWPOINTS IN THE MID TO UPPER 60S AROUND THE FRONT. THESE HIGH DEWPOINTS HAVE LED TO SOME FOG AND STRATUS FORMATION THIS MORNING. BEHIND THE FRONT OVER NORTH CENTRAL WISCONSIN THROUGH UPPER MICHIGAN...DRIER AND COOLER AIR IS FILTERING IN AHEAD OF HIGH PRESSURE OVER NORTHERN ONTARIO. MUCH OF THE SHORT TERM PERIOD FOCUS IS ON THE SHORTWAVE NEAR FARGO AS WELL AS THE COLD FRONT THAT HAS LAYED UP OVER THE SOUTHWESTERN PORTION OF THE FORECAST AREA. REGARDING THE SHORTWAVE...MODELS GENERALLY SUGGEST THE CORE NEAR FARGO ENDS UP TRACKING TO THE EAST OVER THE NEXT 24 HOURS...REACHING CENTRAL UPPER MI BY 12Z MON. HOWEVER...THE TAIL OF THE SHORTWAVE WILL END UP CROSSING THE FORECAST AREA TONIGHT. DPVA FROM THE TAIL OF THE SHORTWAVE...DAYTIME HEATING/INSTABILITY THAT DEVELOPS TO INTERACT WITH CONVERGENCE ALONG THE COLD FRONT...AND INCREASING 850MB MOISTURE TRANSPORT TONIGHT OVER THE FORECAST AREA ALL SUGGEST POTENTIAL FOR SHOWERS AND STORMS OVER THE NEXT 24 HOURS. GIVEN THE TRACK OF THE SHORTWAVE TAIL AND MOISTURE TRANSPORT SIGNAL...THE NORTHWEST HALF OF THE FORECAST AREA STANDS TO HAVE THE BEST SHOT FOR PRECIPITATION. HIGH RESOLUTION MODEL GUIDANCE SUGGEST MUCH OF THE ACTIVITY THIS AFTERNOON AND EVENING SHOULD BE ISOLATED TO SCATTERED AT BEST. THE INCREASE IN 850MB MOISTURE TRANSPORT AFTER MIDNIGHT COULD ALLOW CONVECTION TO INCREASE A BIT MORE IN COVERAGE...THUS HIGHEST CHANCES ARE 06-12Z MONDAY. REGARDING CONVECTIVE HAZARDS. 0-6KM AND 0-3KM SHEAR IS ALL BELOW 20 KT THROUGH TONIGHT...LIMITING SEVERE POTENTIAL. HOWEVER... PRECIPITABLE WATER IS PROGGED IN THE 1.5-1.8 INCH RANGE WHICH WOULD ALLOW THE STORMS TO PRODUCE BRIEF HEAVY RAIN. TEMPERATURES TODAY SHOULD VARY QUITE A BIT ACROSS THE FORECAST AREA. ACROSS THE SOUTHWEST END OF THE FORECAST AREA WHERE THE FRONT HAS STALLED OUT...925MB TEMPS ARE SIMILAR TO YESTERDAY IN THE 21-22C RANGE...SUPPORTING HIGHS INTO THE LOW 80S OR SO. MEANWHILE...IN NORTH CENTRAL WI WHERE 925MB TEMPS ONLY TOP OUT AT 18C...HIGHS MAY ONLY REACH THE MID 70S. SOUTHERLY FLOW ACROSS THE FORECAST AREA TONIGHT SHOULD HELP KEEP BOTH TEMPERATURES AND DEWPOINTS UP...WITH ONLY PRECIPITATION COOLING LOWS. THEREFORE...EXPECT ANOTHER MILD AND SOMEWHAT HUMID NIGHT FOR MID AUGUST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 AM CDT SUN AUG 17 2014 FOCUS FOR MONDAY THROUGH TUESDAY REMAINS ON THE UPPER LOW AND TROUGH CURRENTLY OVER SOUTHERN SASKATCHEWAN AND EASTERN MONTANA. MODELS CONTINUE TO BE IN GOOD AGREEMENT DROPPING THIS TROUGH INTO MN ON MONDAY...INTO THE FORECAST AREA BY 12Z TUE...AND OVER EASTERN WI BY 00Z WED. THE TRACK OF THE TROUGH SUGGESTS THE BEST DYNAMICAL FORCING FOR THE FORECAST AREA OCCURS FROM 18Z MONDAY TO 18Z TUESDAY...MAXIMIZED DURING MONDAY EVENING. THERE SHOULD BE PLENTY OF MOISTURE FOR THE TROUGH TO WORK ON TOO...WITH 1.5-1.75 INCHES OF PRECIPITABLE WATER ALREADY IN PLACE AND IS PROGGED TO REMAIN STEADY THROUGH THE TROUGH PASSAGE. GIVEN THE GOOD CONSISTENCY ON THIS SIGNAL FOR THE TROUGH...FEEL FAIRLY CONFIDENT MUCH OF THE AREA WILL SEE SHOWERS AND STORMS. DAYTIME HEATING INCREASING INSTABILITY FOR MONDAY AND TUESDAY AFTERNOONS SHOULD ONLY HELP MATTERS. THEREFORE... HAVE INCREASED PRECIPITATION CHANCES EVEN MORE. IT DOES APPEAR LOCATIONS WEST OF THE MS RIVER SHOULD SEE PRECIPITATION DIMINISH FOR A TIME FROM 03-12Z TUESDAY OVER THE WEST HALF OF THE FORECAST AREA...THOUGH. 925MB TEMPS ON MONDAY IN THE 20-22C RANGE SHOULD SUPPORT HIGHS IN THE UPPER 70S/LOW 80S...HELD DOWN BY PRECIPITATION. IT WILL LIKELY FEEL A BIT HUMID TOO. 925MB TEMPS ONLY TOP OUT FROM 18-20C ON TUESDAY...AND WITH THE POTENTIAL FOR PRECIPITATION...HIGHS GET KNOCKED DOWN A FEW DEGREES. ALL INDICATIONS ARE THAT THE UPPER LOW AND TROUGH WILL MOVE AWAY FROM THE REGION TUESDAY NIGHT...ALLOWING ANY CONVECTION TO DIMINISH/END TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING. WITH THE AREA PROGGED TO LIE IN AN INFLECTION POINT BETWEEN THE DEPARTING TROUGH AND UPPER RIDGING BUILDING UP ALONG I-29...SUBSIDENCE SHOULD BE IN PLACE TO ALLOW FOR A DRY OVERNIGHT. CLEARING OF THE SKIES COMBINED WITH RECENT RAINS AND DIMINISHING WINDS SHOULD PROMOTE FOG DEVELOPMENT AND THUS ADDED AREAS OF FOG TO THE FORECAST. THE DRY CONDITIONS COULD PERSIST THROUGH WEDNESDAY AS THAT UPPER RIDGE SHIFTS EAST TO I-35. HOWEVER...THERE ARE SIGNS FOR SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP ACROSS IOWA...NORTH OF A WARM FRONTAL BOUNDARY PROGGED TO SET UP ALONG THE MO/IA BORDER. HAVE KEPT SOME LOW CHANCES IN ACROSS THE FAR SOUTHERN PORTION OF THE FORECAST AREA JUST IN CASE. FOR WEDNESDAY NIGHT AND INTO NEXT WEEKEND...THERE IS GOOD MODEL AGREEMENT AMONGST 17.00Z GUIDANCE AS WELL AS PREVIOUS MODELS FOR TROUGHING TO DIG INTO THE PACIFIC NORTHWEST. IN RESPONSE...RIDGING BUILDS DOWNSTREAM TOWARDS THE FORECAST AREA...RESULTING IN A WARM/MOIST AIR ADVECTION PATTERN. THIS WILL LEAD TO MORE CHANCES OF SHOWERS AND THUNDERSTORMS. ITS APPEARING LIKE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING COULD BE AN ENHANCED CHANCE BASED ON ECMWF/GFS MODEL TRENDS. THIS IS ASSOCIATED WITH THE WARM FRONTAL BOUNDARY ALONG THE MO/IA BORDER ON WEDNESDAY LIFTING INTO THE AREA. 1-6 KM SHEAR IS 25 KT OR LESS...SO THINKING HEAVY RAIN SHOULD BE THE MAIN CONCERN. WE MAY BE ABLE TO SQUEEZE IN A DRY DAY ON FRIDAY...AS A SURFACE COOL FRONT PASSES...BUT HARD TO SAY AT THIS TIME. THEN HEADING INTO THE WEEKEND...THERE ARE SOME UNCERTAINTIES WITH THE PACIFIC NORTHWEST TROUGH. THE 17.00Z ECMWF NOW WANTS TO PUSH THE TROUGH EASTWARD WHICH RESULTS IN A RELATIVELY STRONG STORM SYSTEM LIFTING THROUGH THE REGION SATURDAY. THE RESULT COULD BE SOME SEVERE WEATHER. THE GFS HAS A SIMILAR STORM SYSTEM BUT FARTHER OFF TO THE WEST SINCE IT IS SLOWER TO MOVE THE UPPER TROUGH. EITHER SCENARIO WOULD PULL WARMER AND MORE HUMID AIR INTO THE REGION. VERY HARD TO SAY WHAT SUNDAY IS GOING TO LOOK LIKE WITH THE UNCERTAINTY ON UPPER TROUGH PROGRESSION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1142 PM CDT SAT AUG 16 2014 LOOKS LIKE ANOTHER GOOD NIGHT FOR THE FORMATION OF FOG AND LOW STRATUS ACROSS THE AREA. THE WEAK COLD FRONT CONTINUES TO MAKE SLOW SOUTHWARD PROGRESS AND SHOULD EVENTUALLY PASS THROUGH BOTH SITES. HOWEVER...THE WIND FIELD AHEAD OF THE FRONT IS SO LIGHT WITH ONLY A MINOR INCREASE IN SPEEDS BEHIND THE FRONT...THAT IT WILL NOT MAKE MUCH OF AN IMPACT. SOME CLOUDS CURRENTLY WITH THE FRONT...BUT GENERALLY MOSTLY CLEAR AHEAD OF IT. EXPECT TO SEE SOME FOG AND STRATUS DEVELOP BEFORE THE PASSAGE OF THE FRONT AND LOCAL WEB CAM ALREADY SHOWING SIGNS OF THIS OVER THE MISSISSIPPI RIVER CHANNEL. ONCE THE FRONT GOES THROUGH...THE 17.00Z NAM AND 17.03Z RAP BOTH SHOW SOME INCREASE IN THE LOW LEVEL WINDS OUT OF THE EAST TO THE POINT THAT SURFACE DEW POINTS MAY START TO DRY OUT SOME AT KLSE SO THAT THE VISIBILITY MAY NOT GET TOO LOW. A VISIBILITY BELOW A MILE STILL POSSIBLE AT KRST THOUGH. CONDITIONS EXPECTED TO SLOWLY IMPROVE SUNDAY MORNING WITH A RETURN TO VFR CONDITIONS BY EARLY AFTERNOON. THE NAM SUGGESTS THE POSSIBILITY OF SOME SHOWERS AND STORMS IN THE AFTERNOON AS A SHORT WAVE TROUGH COMES OUT OF THE DAKOTAS AND ACROSS MINNESOTA. HOWEVER...ITS FORECAST SOUNDINGS SHOW VERY LITTLE VERTICAL MOTION AND OPTED TO STAY WITH A DRY FORECAST. BETTER CHANCES FOR RAIN MAY COME AFTER 06Z MONDAY AS A STRONGER SHORT WAVE TROUGH APPROACHES. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
335 PM MDT SUN AUG 17 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 330 PM MDT SUN AUG 17 2014 AFTERNOON WATER VAPOR LOOP REVEALED A CLOSED UPPER LOW NORTH OF THE NORTH DAKOTA BORDER WITH A TROUGH AXIS INTO THE WESTERN DAKOTAS. CLUSTERS OF INTENSE CONVECTION WERE DEVELOPING AHEAD OF THIS FEATURE. CYS/RIW RADARS SHOWED A FEW SHOWERS DEVELOPING ALONG A WEAK CONVERGENCE ZONE FROM SOUTHERN NATRONA TO SOUTHERN CONVERSE COUNTY. THE HRRR MODEL COMPOSITE REFLECTIVITY LOOP SHOWED THIS ACTIVITY MOVING ACROSS EAST CENTRAL WYOMING THROUGH LATE AFTERNOON THEN DISSIPATING. WITH VERY DRY SUB-CLOUD LAYER...CAN EXPECT GUSTY WINDS AND LITTLE IF ANY MEASURABLE RAINFALL WITH THESE SHOWERS. MAIN CONCERN CONTINUES TO BE FIRE WEATHER IMPACTS FROM THE GUSTY WINDS AND LOW HUMIDITY FOR ELEVATIONS BELOW 8000 FT. RED FLAG WARNING REMAINS IN EFFECT FOR ALL BUT THE SIERRA MADRE/SNOWY RANGE ZONES THROUGH 7 PM. GETTING CLOSE TO RED FLAG CRITERIA OVER THE NEBRASKA PANHANDLE ZONES BORDERING WYOMING. CONDITIONS WILL IMPROVE THIS EVENING AS WINDS DECREASE AND HUMIDITIES INCREASE. A BLEND OF THE 12Z SHORT RANGE MODEL GUIDANCE HANDLES THE LARGE SCALE PATTERN PRETTY WELL. THE UPPER TROUGH ADVANCES EAST SOUTHEAST ACROSS THE DAKOTAS AND MIDWEST DURING THE NEXT 24 HOURS. MEANWHILE...A UPPER RIDGE EXPANDS NORTHWEST FROM THE FOUR CORNERS REGION WITH A HEALTHY SURGE OF SUBTROPICAL MOISTURE MOVING INTO THE CENTRAL ROCKIES TUESDAY. PRECIP WATER VALUES MONDAY WILL RANGE FROM A HALF INCH WEST OF THE LARAMIE RANGE TO AROUND AN INCH FOR THE HIGH PLAINS. TUESDAY...PRECIP WATER INCREASE TO AROUND 1.25 INCHES EAST OF THE LARAMIE AND 0.75-1.0 INCH TO THE WEST. DIURNAL CONVECTIVE COVERAGE MONDAY WILL BE ISOLATED AND CONFINED TO THE MOUNTAINS. THE AIRMASS OVER THE PLAINS WILL REMAIN CAPPED PRECLUDING SHOWER DEVELOPMENT. SHOWER/TSTORM COVERAGE INCREASES TO SCATTERED TUESDAY AFTERNOON/EVENING AS A POTENT SHORTWAVE RIDES NORTHEAST ACROSS WYOMING AND COLORADO. DOWNSLOPING WESTERLY WINDS WILL LIMIT QPF OVER THE EASTERN WYOMING PLAINS...WITH AT LEAST O.25 INCH AMOUNTS POSSIBLE OVER THE HIGHER TERRAIN AND WESTERN NEBRASKA PANHANDLE. ABOVE NORMAL WARMTH WILL CONTINUE MONDAY LOWER ELEVATIONS MONDAY AND EAST OF THE LARAMIE RANGE TUESDAY WITH HIGHS IN THE 80S TO LOWER 90S. TEMPERATURES WILL TREND SLIGHTLY COOLER WEST OF THE LARAMIE RANGE TUESDAY DUE TO GREATER CLOUD AND SHOWER COVERAGE. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 300 PM MDT SUN AUG 17 2014 WARM AND MAINLY DRY WEATHER EXPECTED ACROSS THE CWA WEDNESDAY AND THURSDAY THOUGH A FEW SHOWERS/TSTRMS POSSIBLE OVER THE HIGHER SRN MTNS BOTH AFTERNOONS/EARLY EVENINGS. CHANGES LOOK TO BE IN THE OFFING BEGINNING FRIDAY AND CONTINUING INTO THE WEEKEND AS AN UPPER TROF SETTLES OVER THE NW PART OF THE COUNTRY AND A PUSH OF COOLER CANADIAN AIR DROPS DOWN THE HIGH PLAINS SATURDAY AND SATURDAY NIGHT WITH THE EC CONTINUING TO BE MUCH MORE BULLISH IN PUSHING THIS COOL AIR ACROSS THE CWA BY LATE SATURDAY...SETTING UP A MILD DAY FOR SUNDAY. EC HAS BEEN CONSISTENT WITH THIS. SHOULD ALSO SEE A BIT OF AN UPTICK IN CONVECTION FRIDAY AND SATURDAY AS THE UPPER TROF NEARS WITH ANY ASSOCIATED IMPULSES ROUNDING THE BASE OF IT PASSING ACROSS THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED AT 1120 AM MDT SUN AUG 17 2014 VFR CONDITIONS THROUGH MONDAY WITH A RATHER DRY AIR MASS OVER THE AREA. A WEAK SFC COOL FRONT WILL MOVE SOUTH ACROSS WY AND WRN NEBRASKA TONIGHT SWITCHING WINDS TO LIGHT NORTHERLY OVER THE PLAINS. && .FIRE WEATHER... ISSUED AT 220 PM MDT SUN AUG 17 2014 NORTHWEST WINDS GUSTS OF 25 TO 35 MPH COMBINED WITH RELATIVE HUMDITIES OF 10 TO 15 PERCENT WILL CREATE CONDITIONS CONDUCIVE TO RAPID FIRE GROWTH FOR AREAS BELOW 8000 FEET IN SOUTHEAST WYOMING THROUGH EARLY EVENING. GUSTS APPROACHING 25 MPH AND 10 TO 15 PERCENT HUMIDITIES OVER THE FAR WESTERN NEBRASKA PANHANDLE WILL ENHANCE THE FIRE WEATHER THREAT THIS AFTERNOON. FIRE WEATHER CONCERNS WILL BECOME MINIMAL MONDAY AND TUESDAY AS AN INFLUX OF MONSOON MOISTURE FROM THE SOUTHWEST INCREASES CHANCES FOR WETTING RAINS EARLY THIS WEEK. WINDS WILL BE LIGHTER AS WELL. DRIER CONDITIONS RETURN MID WEEK FOLLOWED BY A SLIGHT INCREASE IN MOISTURE LATE IN THE WEEK. ABOVE AVERAGE TEMPERATURES THIS WEEK WILL GRADUALLY COOL NEXT WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>304-306- 308>310. NE...NONE. && $$ SHORT TERM...JAMSKI LONG TERM...RE AVIATION...RE FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1120 AM MDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1050 AM MDT SUN AUG 17 2014 LATE MORNING WATER VAPOR LOOP SHOWED A CLOSED UPPER LOW DRIFTING EAST ACROSS SOUTHERN SASKATCHEWAN PROVINCE WITH A TROUGH EXTENDING INTO MT/NORTHERN WY. UPPER HIGH WAS SITUATED OVER THE DESERT SOUTHWEST WITH ZONAL FLOW ALOFT OVER SOUTHEAST WY/WESTERN NE. 12Z RIW/DEN SOUNDINGS INDICATED A VERY DRY LOW/MID LAYER WITH PRECIP WATER VALUES OF .42/.52 INCH RESPECTIVELY. THE RIW SOUNDING DEPICTED 35 TO 45 KT WESTERLY WINDS JUST ABOVE 600MB. AS TEMPERATURES RISE TO AROUND 90 THIS AFTERNOON...EFFICIENT MIXING OF MID LEVEL WINDS TO THE SURFACE WILL RESULT IN GUSTS TO AROUND 30 KT FOR MUCH OF SOUTHEAST WY. HUMIDITIES WILL DROP TO 10 TO 15 PERCENT BELOW 8000 FT. CURRENT RED FLAG WARNING FOR ALL WY ZONES EXCEPT THE SIERRA MADRE AND SNOWY RANGES ON TRACK. WILL NEED TO CLOSELY MONITOR THE WESTERN NE PANHANDLE FOR POTENTIAL CRITICAL FIRE WEATHER CONDITIONS WITH WIND GUSTS OF 15 TO 20 MPH AND HUMIDITIES DROPPING TO AROUND 15 PERCENT...ESPECIALLY THOSE COUNTIES BORDERING WY. LATEST HRRR MODEL KEEPS THE CWA DRY THIS AFTERNOON AND EARLY EVENING AS SHOWER/TSTORM ACTIVITY WILL BE CONFINED TO CENTRAL/EASTERN CO AND BLACK HILLS TO NORTHERN NE EASTWARD. THEREFORE...REMOVED SMALL POPS FOR THE MOUNTAINS. RAISED MAX TEMPERATURES A FEW DEGREES FOR THE PLAINS. && .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 500 AM MDT SUN AUG 17 2014 MAIN CONCERN FOR TODAY WILL ONCE AGAIN BE FIRE WEATHER AS CRITICAL CONDITIONS ARE ANTICIPATED FOR MUCH OF SOUTHEAST WYOMING. AN UPPER LEVEL SHORTWAVE CURRENTLY OVER IDAHO PER WATER VAPOR IMAGERY WILL MOVE ACROSS NORTHERN WYOMING TODAY AND WILL SYNC UP WITH A STRONGER UPPER TROUGH MOVING ALONG THE US/CANADIAN BORDER. THE COMBINATION OF FEATURES WILL DEEPEN THE LEE SIDE SFC PRESSURE TROUGH THROUGH THE DAY WITH BREEZY NORTHWEST WINDS DEVELOPING ACROSS SOUTHEAST WYOMING AS THE SFC PRESSURE GRADIENT STRENGTHENS. GUSTS OF 25 TO 35 MPH LOOK COMMON OVER THIS AREA THRU THE AFTERNOON AS FORECAST SOUNDINGS SUGGEST THE TOP OF THE MIXING LEVEL WILL BE UP BETWEEN 500 AND 600 MB WHERE WINDS WILL BE 30 TO 35 KT. THE ALREADY DRY BOUNDARY LAYER AIRMASS COMBINED WITH DRY AND WARM DOWNSLOPE WINDS WILL TANK HUMIDITIES FAIRLY QUICKLY LATE THIS MORNING OVER SOUTHEAST WYOMING...WITH HUMIDITIES EXPECTED TO REMAIN IN THE LOW TEENS FOR MUCH OF THE AFTERNOON. THE COMBINATION OF LOW RHS AND GUSTY WINDS WILL CREATE CRITICAL FIRE WEATHER CONDITIONS OVER MUCH OF SOUTHEAST WYOMING WITH THE FOCUS ON AREAS BELOW 8000 FEET. STARTED THE RFW SLIGHTLY EARLIER THAN PREVIOUS ISSUANCE AS WINDS SHOULD INCREASE QUICKLY THROUGH THE LATE MORNING...AND ADDED IN FWZ 302 TO ACCOUNT FOR THE LOWER ELEVATIONS OF THIS ZONE WHICH SAW MARGINAL CRITICAL CONDITIONS YESTERDAY AND WILL LIKELY BREACH CRITICAL THRESHOLDS AGAIN TODAY. REGARDING STORM CHANCES ACROSS THE CWA...CONVECTION ASSOCIATED WITH THE SHORTWAVE FEATURED APPEARED TO BE SOMEWHAT LIMITED OVER OREGON AND IDAHO YESTERDAY WITHIN THE DRY AIRMASS. EXPECT A SIMILAR TREND FOR OUR AREA TODAY WITH MINIMAL DEEP CONVECTION OVER THE CWA. LOOKING INSTEAD AT SOME TOWERING CU AND PERHAPS A SHOWER OR TWO OVER THE MOUNTAINS WHERE OROGRAPHIC EFFECTS WILL AIDE IN SOME CONVECTIVE DEVELOPMENT. LACK OF DEEP LAYER MOISTURE SHOULD KEEP TSTORM CHANCES MINIMAL THO. A SURFACE FRONT WILL DROP SOUTH ACROSS THE PLAINS EARLY THIS EVENING AND OVERNIGHT WITH AN INCREASE IN LLVL MOISTURE AND A SFC WIND SHIFT TO THE NORTH THEN NORTHEAST WITH FROPA. MODELS SUGGEST THAT MID LEVEL MOISTURE WILL INCREASE OVER THE ROCKIES THROUGH THE DAY MONDAY WITH STRENGTHENING FLOW ALOFT. NORTHEAST UPSLOPE FLOW IN PLACE ACROSS THE PLAINS COMBINED WITH INCREASING MOISTURE WILL EASE FIRE WEATHER CONCERNS OVER THE FORECAST AREA...WITH CHANCES FOR SHOWERS AND TSTORMS RETURNING TO THE MOUNTAINS OF SOUTHEAST WYOMING AND NEARBY LOWER ELEVATIONS IN THE AFTERNOON. MODELS HINT AT A WAA PATTERN DEVELOPING MONDAY NIGHT AHEAD OF A SHORTWAVE MOVING UP FROM THE SOUTHWEST WITH SOUTHWESTERLY H7 WINDS INCREASING TO 15 TO 20 KT OVERNIGHT. COULD SEE CONVECTION CONTINUE THRU EARLY TUESDAY MORNING AS A RESULT...WITH THE MAIN FOCUS ACROSS THE PANHANDLE WHERE WAA AND DEEPEST MOISTURE WILL BE COLLOCATED WITH OROGRAPHIC LIFT OFF THE PINE RIDGE. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 500 AM MDT SUN AUG 17 2014 MODELS VERY SIMILAR TUESDAY BRINGING A SHORTWAVE THROUGH THE RIDGE OVER SOUTHERN WYOMING AND DEVELOPING SOME QPF OVER THE WESTERN MOUNTAINS TUESDAY AFTERNOON. BOTH THE GFS AND ECMWF SPREAD THIS MOISTURE OUT INTO THE PANHANDLE TUESDAY AFTERNOON...SO KEPT SLIGHT CHANCE POPS GOING FOR MOST AREAS INTO TUESDAY EVENING. BEST CHANCES FOR SHOWERS LOOKS TO BE WEST OF THE LARAMIE RANGE THOUGH AND THIS IS WHERE HIGHEST POPS WERE PLACED. DRIER AIR FOR WEDNESDAY...BUT STILL SOME CHANCES FOR THE SNOWY AND SIERRA MADRE RANGES DURING THE AFTERNOON. MOST AREAS SHOULD STAY DRY WITH WEST TO NORTHWEST DOWNSLOPING WINDS OFF THE LARAMIE RANGE. A DIFFERENT STORY FOR FRIDAY AND MODELS BEGIN TO DIVERGE. THE GFS SHOWING A POTENT SHORTWAVE MOVING INTO THE SOUTHEASTERN CWFA FRIDAY MORNING WITH WIDESPREAD SHOWERS ACTIVITY ACROSS THE SOUTHERN PANHANDLE BACK INTO EXTREME SOUTHEAST WYOMING. ECMWF MUCH WEAKER WITH THIS SHORTWAVE AND KEEPS POPS MUCH LOWER THAN THE GFS. ECMWF DOES EVENTUALLY BRING SOME QPF INTO THE AREA...MAINLY ACROSS OUR NORTHERN AND EASTERN ZONES...SO DID KEEP SOME SLIGHT CHANCE TO LOW CHANCE POPS GOING IN THE FORECAST FOR FRIDAY. ENTERING SATURDAY...GFS SHOWING A 90KT UPPER LEVEL JET MOVING INTO CENTRAL WYOMING SATURDAY MORNING. 700MB WINDS ON THE INCREASE AS WELL...WITH 30KT DEVELOPING FRIDAY MORNING OUT WEST. ORIENTATION ON ECMWF A LITTLE DIFFERENT WITH THE TROUGH MORE PRONOUNCED AND COLDER. ECMWF 700MB TEMPERATURES SATURDAY AFTERNOON ACROSS NORTHERN WYOMING DOWN TO 0 TO -2C. COULD BE A SIGNIFICANT COOL DOWN SHOULD THE ECMWF FORECAST COME TRUE. FOR NOW...DID NOT COOL TEMPERATURES AS MUCH AS WHAT THE ECMWF MIGHT GO FOR...BUT DID GO LOWER ON TEMPERATURES. LARGE POSSIBILITIES FOR A TEMPERATURE BUST AS THERE IS A 10C DIFFERENCE IN 700MB TEMPERATURES BETWEEN THE TWO MEDIUM RANGE MODELS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED AT 1120 AM MDT SUN AUG 17 2014 VFR CONDITIONS THROUGH MONDAY WITH A RATHER DRY AIR MASS OVER THE AREA. A WEAK SFC COOL FRONT WILL MOVE SOUTH ACROSS WY AND WRN NEBRASKA TONIGHT SWITCHING WINDS TO LIGHT NORTHERLY OVER THE PLAINS. && .FIRE WEATHER... ISSUED AT 500 AM MDT SUN AUG 17 2014 RED FLAG WARNING REMAINS IN EFFECT FOR MUCH OF SOUTHEAST WYOMING THIS AFTERNOON FOR NORTHWEST WIND GUSTS OF 25 TO 35 MPH COMBINING WITH HUMIDITIES DROPPING TO THE LOW TEENS. THE HIGHEST THREAT FOR CRITICAL CONDITIONS WILL BE IN AREAS BELOW 8000 FEET. INCREASING MOISTURE AT THE SFC AND ALOFT WILL COMBINE WITH GENERALLY WEAKER WINDS TO DIMINISH FIRE WEATHER CONCERNS FOR MONDAY AND TUESDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE EARLY NEXT WEEK AS WELL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>304-306- 308>310. NE...NONE. && $$ UPDATE...JAMSKI SHORT TERM...RJM LONG TERM...CLAYCOMB AVIATION...RE FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1109 AM MDT SUN AUG 17 2014 .UPDATE... ISSUED AT 1050 AM MDT SUN AUG 17 2014 LATE MORNING WATER VAPOR LOOP SHOWED A CLOSED UPPER LOW DRIFTING EAST ACROSS SOUTHERN SASKATCHEWAN PROVINCE WITH A TROUGH EXTENDING INTO MT/NORTHERN WY. UPPER HIGH WAS SITUATED OVER THE DESERT SOUTHWEST WITH ZONAL FLOW ALOFT OVER SOUTHEAST WY/WESTERN NE. 12Z RIW/DEN SOUNDINGS INDICATED A VERY DRY LOW/MID LAYER WITH PRECIP WATER VALUES OF .42/.52 INCH RESPECTIVELY. THE RIW SOUNDING DEPICTED 35 TO 45 KT WESTERLY WINDS JUST ABOVE 600MB. AS TEMPERATURES RISE TO AROUND 90 THIS AFTERNOON...EFFICIENT MIXING OF MID LEVEL WINDS TO THE SURFACE WILL RESULT IN GUSTS TO AROUND 30 KT FOR MUCH OF SOUTHEAST WY. HUMIDITIES WILL DROP TO 10 TO 15 PERCENT BELOW 8000 FT. CURRENT RED FLAG WARNING FOR ALL WY ZONES EXCEPT THE SIERRA MADRE AND SNOWY RANGES ON TRACK. WILL NEED TO CLOSELY MONITOR THE WESTERN NE PANHANDLE FOR POTENTIAL CRITICAL FIRE WEATHER CONDITIONS WITH WIND GUSTS OF 15 TO 20 MPH AND HUMIDITIES DROPPING TO AROUND 15 PERCENT...ESPECIALLY THOSE COUNTIES BORDERING WY. LATEST HRRR MODEL KEEPS THE CWA DRY THIS AFTERNOON AND EARLY EVENING AS SHOWER/TSTORM ACTIVITY WILL BE CONFINED TO CENTRAL/EASTERN CO AND BLACK HILLS TO NORTHERN NE EASTWARD. THEREFORE...REMOVED SMALL POPS FOR THE MOUNTAINS. RAISED MAX TEMPERATURES A FEW DEGREES FOR THE PLAINS. && .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 500 AM MDT SUN AUG 17 2014 MAIN CONCERN FOR TODAY WILL ONCE AGAIN BE FIRE WEATHER AS CRITICAL CONDITIONS ARE ANTICIPATED FOR MUCH OF SOUTHEAST WYOMING. AN UPPER LEVEL SHORTWAVE CURRENTLY OVER IDAHO PER WATER VAPOR IMAGERY WILL MOVE ACROSS NORTHERN WYOMING TODAY AND WILL SYNC UP WITH A STRONGER UPPER TROUGH MOVING ALONG THE US/CANADIAN BORDER. THE COMBINATION OF FEATURES WILL DEEPEN THE LEE SIDE SFC PRESSURE TROUGH THROUGH THE DAY WITH BREEZY NORTHWEST WINDS DEVELOPING ACROSS SOUTHEAST WYOMING AS THE SFC PRESSURE GRADIENT STRENGTHENS. GUSTS OF 25 TO 35 MPH LOOK COMMON OVER THIS AREA THRU THE AFTERNOON AS FORECAST SOUNDINGS SUGGEST THE TOP OF THE MIXING LEVEL WILL BE UP BETWEEN 500 AND 600 MB WHERE WINDS WILL BE 30 TO 35 KT. THE ALREADY DRY BOUNDARY LAYER AIRMASS COMBINED WITH DRY AND WARM DOWNSLOPE WINDS WILL TANK HUMIDITIES FAIRLY QUICKLY LATE THIS MORNING OVER SOUTHEAST WYOMING...WITH HUMIDITIES EXPECTED TO REMAIN IN THE LOW TEENS FOR MUCH OF THE AFTERNOON. THE COMBINATION OF LOW RHS AND GUSTY WINDS WILL CREATE CRITICAL FIRE WEATHER CONDITIONS OVER MUCH OF SOUTHEAST WYOMING WITH THE FOCUS ON AREAS BELOW 8000 FEET. STARTED THE RFW SLIGHTLY EARLIER THAN PREVIOUS ISSUANCE AS WINDS SHOULD INCREASE QUICKLY THROUGH THE LATE MORNING...AND ADDED IN FWZ 302 TO ACCOUNT FOR THE LOWER ELEVATIONS OF THIS ZONE WHICH SAW MARGINAL CRITICAL CONDITIONS YESTERDAY AND WILL LIKELY BREACH CRITICAL THRESHOLDS AGAIN TODAY. REGARDING STORM CHANCES ACROSS THE CWA...CONVECTION ASSOCIATED WITH THE SHORTWAVE FEATURED APPEARED TO BE SOMEWHAT LIMITED OVER OREGON AND IDAHO YESTERDAY WITHIN THE DRY AIRMASS. EXPECT A SIMILAR TREND FOR OUR AREA TODAY WITH MINIMAL DEEP CONVECTION OVER THE CWA. LOOKING INSTEAD AT SOME TOWERING CU AND PERHAPS A SHOWER OR TWO OVER THE MOUNTAINS WHERE OROGRAPHIC EFFECTS WILL AIDE IN SOME CONVECTIVE DEVELOPMENT. LACK OF DEEP LAYER MOISTURE SHOULD KEEP TSTORM CHANCES MINIMAL THO. A SURFACE FRONT WILL DROP SOUTH ACROSS THE PLAINS EARLY THIS EVENING AND OVERNIGHT WITH AN INCREASE IN LLVL MOISTURE AND A SFC WIND SHIFT TO THE NORTH THEN NORTHEAST WITH FROPA. MODELS SUGGEST THAT MID LEVEL MOISTURE WILL INCREASE OVER THE ROCKIES THROUGH THE DAY MONDAY WITH STRENGTHENING FLOW ALOFT. NORTHEAST UPSLOPE FLOW IN PLACE ACROSS THE PLAINS COMBINED WITH INCREASING MOISTURE WILL EASE FIRE WEATHER CONCERNS OVER THE FORECAST AREA...WITH CHANCES FOR SHOWERS AND TSTORMS RETURNING TO THE MOUNTAINS OF SOUTHEAST WYOMING AND NEARBY LOWER ELEVATIONS IN THE AFTERNOON. MODELS HINT AT A WAA PATTERN DEVELOPING MONDAY NIGHT AHEAD OF A SHORTWAVE MOVING UP FROM THE SOUTHWEST WITH SOUTHWESTERLY H7 WINDS INCREASING TO 15 TO 20 KT OVERNIGHT. COULD SEE CONVECTION CONTINUE THRU EARLY TUESDAY MORNING AS A RESULT...WITH THE MAIN FOCUS ACROSS THE PANHANDLE WHERE WAA AND DEEPEST MOISTURE WILL BE COLLOCATED WITH OROGRAPHIC LIFT OFF THE PINE RIDGE. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 500 AM MDT SUN AUG 17 2014 MODELS VERY SIMILAR TUESDAY BRINGING A SHORTWAVE THROUGH THE RIDGE OVER SOUTHERN WYOMING AND DEVELOPING SOME QPF OVER THE WESTERN MOUNTAINS TUESDAY AFTERNOON. BOTH THE GFS AND ECMWF SPREAD THIS MOISTURE OUT INTO THE PANHANDLE TUESDAY AFTERNOON...SO KEPT SLIGHT CHANCE POPS GOING FOR MOST AREAS INTO TUESDAY EVENING. BEST CHANCES FOR SHOWERS LOOKS TO BE WEST OF THE LARAMIE RANGE THOUGH AND THIS IS WHERE HIGHEST POPS WERE PLACED. DRIER AIR FOR WEDNESDAY...BUT STILL SOME CHANCES FOR THE SNOWY AND SIERRA MADRE RANGES DURING THE AFTERNOON. MOST AREAS SHOULD STAY DRY WITH WEST TO NORTHWEST DOWNSLOPING WINDS OFF THE LARAMIE RANGE. A DIFFERENT STORY FOR FRIDAY AND MODELS BEGIN TO DIVERGE. THE GFS SHOWING A POTENT SHORTWAVE MOVING INTO THE SOUTHEASTERN CWFA FRIDAY MORNING WITH WIDESPREAD SHOWERS ACTIVITY ACROSS THE SOUTHERN PANHANDLE BACK INTO EXTREME SOUTHEAST WYOMING. ECMWF MUCH WEAKER WITH THIS SHORTWAVE AND KEEPS POPS MUCH LOWER THAN THE GFS. ECMWF DOES EVENTUALLY BRING SOME QPF INTO THE AREA...MAINLY ACROSS OUR NORTHERN AND EASTERN ZONES...SO DID KEEP SOME SLIGHT CHANCE TO LOW CHANCE POPS GOING IN THE FORECAST FOR FRIDAY. ENTERING SATURDAY...GFS SHOWING A 90KT UPPER LEVEL JET MOVING INTO CENTRAL WYOMING SATURDAY MORNING. 700MB WINDS ON THE INCREASE AS WELL...WITH 30KT DEVELOPING FRIDAY MORNING OUT WEST. ORIENTATION ON ECMWF A LITTLE DIFFERENT WITH THE TROUGH MORE PRONOUNCED AND COLDER. ECMWF 700MB TEMPERATURES SATURDAY AFTERNOON ACROSS NORTHERN WYOMING DOWN TO 0 TO -2C. COULD BE A SIGNIFICANT COOL DOWN SHOULD THE ECMWF FORECAST COME TRUE. FOR NOW...DID NOT COOL TEMPERATURES AS MUCH AS WHAT THE ECMWF MIGHT GO FOR...BUT DID GO LOWER ON TEMPERATURES. LARGE POSSIBILITIES FOR A TEMPERATURE BUST AS THERE IS A 10C DIFFERENCE IN 700MB TEMPERATURES BETWEEN THE TWO MEDIUM RANGE MODELS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 500 AM MDT SUN AUG 17 2014 VFR CONDITIONS NEXT 24 HOURS FOR ALL SOUTHEAST WYOMING AND NEBRASKA PANHANDLE AIRPORTS. MAIN CONCERN TODAY WILL BE GUSTY WEST WINDS ACROSS SOUTHEAST WYOMING. COULD SEE GUSTS APPROACHING 30KT AT KRWL AND KLAR THAT COULD PRODUCE SOME LOW LEVEL TURBULENCE ON TAKEOFFS AND LANDINGS. SHOULD SEE MOSTLY CLEAR SKIES TODAY. && .FIRE WEATHER... ISSUED AT 500 AM MDT SUN AUG 17 2014 RED FLAG WARNING REMAINS IN EFFECT FOR MUCH OF SOUTHEAST WYOMING THIS AFTERNOON FOR NORTHWEST WIND GUSTS OF 25 TO 35 MPH COMBINING WITH HUMIDITIES DROPPING TO THE LOW TEENS. THE HIGHEST THREAT FOR CRITICAL CONDITIONS WILL BE IN AREAS BELOW 8000 FEET. INCREASING MOISTURE AT THE SFC AND ALOFT WILL COMBINE WITH GENERALLY WEAKER WINDS TO DIMINISH FIRE WEATHER CONCERNS FOR MONDAY AND TUESDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE EARLY NEXT WEEK AS WELL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>304-306- 308>310. NE...NONE. && $$ UPDATE...JAMSKI SHORT TERM...RJM LONG TERM...CLAYCOMB AVIATION...CLAYCOMB FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1129 PM MDT MON AUG 18 2014 .UPDATE... ISSUED AT 820 PM MDT MON AUG 18 2014 UPDATED MOST POP FORECASTS, REMOVING POPS OVER THE PLAINS AND EASTERN MOUNTAINS, WHILE ADDING/EXTENDING PRECIP CHANCES OVER THE SOUTHWEST MOUNTAINS AND SAN LUIS VALLEY...AS AREA OF TSRA OVER THE SAN JUANS WILL MOVE EAST ACROSS LOWER ELEVATIONS BEFORE ENDING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 259 PM MDT MON AUG 18 2014 THE UPR RIDGE IS STILL CENTERED NR THE FOUR CORNERS AREA TODAY AND PRECIPITABLE WATER VALUES ARE SIMILAR TO WHAT THEY WERE YESTERDAY. ISOLATED SHOWERS AND TSTMS HAVE DEVELOPED OVR SOME OF THE MOUNTAIN AREAS AS OF 1930Z. SHOULD SEE COVERAGE OVR THE MTNS INCREASE THIS AFTERNOON. HRRR AND RAP SHOW PCPN DEVELOPING/MOVING OVR THE SERN PLAINS AND PORTIONS OF THE SAN LUIS VALLEY LATER THIS AFTERNOON AND THIS EVENING. THE HRRR AND RAP HAVE PCPN ENDING IN MOST LOCATIONS BY LATE EVENING...BUT SHOW THE POTENTIAL FOR SOME CONTINUING OVR THE SAN JUAN MTNS INTO THE LATE NIGHT HOURS. AS AN UPR TROF DIGS INTO SRN CA TONIGHT AND TUESDAY...THE UPR RIDGE OVR OUR AREA SHIFTS EASTWARD. THIS PUSHES A LITTLE BETTER MSTR INTO WRN CO FOR TUE...WITH PRECIPITABLE WATER VALUES INCREASING SLIGHTLY OVR THE CONTDVD. AS A RESULT THERE SHOULD BE MORE WIDESPREAD SHOWER AND TSTM ACTIVITY ALONG THE CONTDVD TOMORROW. THE ERN MTNS WL LIKELY SEE SCT PCPN DEVELOPING IN THE AFTERNOON HOURS...WHILE THE SERN PLAINS SHOULD JUST SEE A FEW SHOWERS OR STORMS DEVELOP. HIGH TEMPS ON TUE SHOULD BE 5-8 DEGREES ABOVE AVERAGE OVR THE SERN PLAINS...AND AROUND NORMAL IN THE SAN LUIS VALLEY AND UPR ARKANSAS RIVER VALLEY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 259 PM MDT MON AUG 18 2014 ...ACTIVE WEATHER FOR AT LEAST THE NEXT WEEK... MODELS ARE NOW IN REASONABLE AGREEMENT THAT THE CUTOFF LOW OFF THE CA COAST WILL PHASE WITH THE TROUGH MOVING INTO THE PACNW...AND THIS WILL LEAD TO AN ENHANCED MONSOONAL PATTERN FOR THE LATTER PART OF THIS WEEK AND BEYOND. A COUPLE OF ADDITIONAL SHORTWAVES WILL MOVE THROUGH THE LONGWAVE TROUGH PATTERN THAT IS OVER WRN CANADA...BRINGING THE THREAT FOR PERIODS OF HEAVY RAIN TO OUR AREA. TUE NIGHT...EXPECT ISOLD STORMS TO PERSIST OVER THE CONTDVD AS THE PLUME BEGINS TO MOVE OVR WRN CO. BY LATE WED THE TROUGH AND ABSORBED CUTOFF WILL MOVE INTO NW AZ/SW UT...AND THE THREAT OF HEAVY BANDS OF CONVECTION WILL CONTINUE FOR THE SW MTS AND CONTDVD. DEPENDING ON WHAT HAS ALREADY FALLEN OVR THE MTS WE COULD SEE THE THREAT OF MORE FLASH FLOODING AND RISK OF SLIDES FOR THE MT AREAS. TIMING FOR OUR CWA`S STAGES IN THE PRO CYCLING CHALLENGE DOES NOT LOOK FAVORABLE AS THE STRONGEST DYNAMICS FROM THIS SYSTEM MOVE THROUGH ON THURSDAY. THAT IS WHEN THE CORE OF A 100 KT JET STREAK MOVES THROUGH CO. THIS IS PRETTY ROBUST FOR AN AUGUST SYSTEM. WITH H6 TEMPS AT MINUS 2C OR LOWER IN THE CORE OF THE LOW...COULD EASILY SEE SOME SNOW FOR ELEVS ABOVE 12K FEET BY FRI MORNING. THE GFS BRINGS US A BIT OF A BREAK IN THE ACTION ON SATURDAY BEFORE ANOTHER FRONT COMES THROUGH SAT NIGHT...FOLLOWED BY A THIRD SYSTEM SUN OR MON. THE ECMWF HAS SOME OF THE HEAVIEST QPF ON FRI AND CONTINUES THE ONSLAUGHT THROUGH THE WEEKEND. A BIT HARD TO SAY WHEN THE HEAVIEST RAIN WILL FALL...BUT THE THREAT OF HEAVY PRECIP WILL CERTAINLY BE WITH US SO LONG AS THIS PARADE OF SHORTWAVES CONTINUE...AT LEAST THROUGH THE FIRST DAYS OF NEXT WEEK. ENSEMBLE POPS LOOKED MUCH TOO LOW SO HAVE RAISED POPS BY AT LEAST 10 PERCENT OVER THIS TIME FRAME FOR BOTH THE PLAINS AND MTS...WHILE THE MTS WILL SEE THE BEST SHOT AT HEAVY PRECIP. TEMPS WILL TREND DOWNWARD THROUGH THE PERIOD...STARTING IN THE NR 90 RANGE FOR TUE-THU...AND THEN FALLING INTO THE 80S AND POSSIBLY LOWER FOR THE PLAINS NEXT WEEKEND. LOOKS LIKE THE FORECAST WILL REMAIN CHALLENGING FOR THE REST OF THIS MONTH. ROSE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1125 PM MDT MON AUG 18 2014 STILL SOME VERY ISOLATED TSRA LINGERING OVER THE SANGRES AND SAN JUANS AS OF 0530Z...EXPECT THESE TO END BY 08Z WITH VFR CONDITIONS ACROSS THE AREA...INCLUDING THE TAF SITES...FOR THE REMAINDER OF THE NIGHT. ON TUESDAY...MOISTURE INCREASES ACROSS WESTERN COLORADO AND EXPECT TSRA TO BE MORE NUMEROUS OVER THE HIGHER TERRAIN IN THE AFTERNOON. HAVE INCLUDED A VCTS MENTION AT BOTH KALS AND KCOS FOR LATE AFTERNOON INTO THE EVENING...THOUGH STORMS WILL BE FAIRLY HIGH BASED WITH ONLY BRIEF MVFR CONDITIONS UNDER THE STRONGEST CELLS. TSRA LESS LIKELY AT KPUB...THOUGH GUSTY OUTFLOW WINDS CERTAINLY POSSIBLE...ESPECIALLY 22Z-02Z PERIOD. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PETERSEN SHORT TERM...28 LONG TERM...ROSE AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1102 PM MDT MON AUG 18 2014 .SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT) ISSUED AT 333 PM MDT MON AUG 18 2014 BIG CHANGES WILL OCCUR OVER THE NEXT 24 HOURS AS AN UNSEASONABLY STRONG AND NEARLY VERTICALLY STACKED TROUGH...CURRENTLY OVER CALIFORNIA...MOVES EAST INTO THE GREAT BASIN. THIS BRINGS EASTERN UTAH AND WESTERN COLORADO INTO IDEAL POSITION FOR DEEP SUBTROPICAL MOISTURE TO ADVECT INTO THE REGION. PRECIPITABLE WATER VALUES OF 1 TO 1.3 INCH ARE EXPECTED TO COVER EASTERN UTAH AND EVEN EXTREME WESTERN COLORADO BY LATE TUESDAY AFTERNOON. THIS IS ALMOST 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. MODELS ARE FORECASTING MULTIPLE VORT MAXES TO REACH THE UT/CO BORDER THROUGHOUT THE DAY FROM NOON TO MIDNIGHT. THERE IS SOME UNCERTAINTY ON THE TIMING OF H3 JET SUPPORT OF 60KTS REACHING THE AREA...WHICH WILL HELP TO PROVIDE ASCENT IN THE UNIMPRESSIVE CAPE AND SHEAR ENVIRONMENT. EXPECTING CLOUD COVER TO HINDER INSTABILITY DURING THE DAY...HOWEVER THIS SCENARIO COULD CHANGE IF SUFFICIENT CLEAR AIR IS ABOUND BY LATE MORNING. THE RAP SHOWS JET SUPPORT INCHING INTO EASTERN UTAH AND SOUTHWEST COLORADO DURING THE MORNING ON TUESDAY...HOWEVER THE NAM AND GFS SHOW THE BEST JET SUPPORT ON TUESDAY NIGHT AND WEDNESDAY MORNING. STORM MOTION WILL BE DECENT FOR TUESDAY - ABOUT 20 TO 30 KTS...SO COULD NOT JUSTIFY A FLASH FLOOD WATCH AT THIS TIME. IT WILL RAIN IN MANY LOCATIONS BY TUESDAY NIGHT...BUT ONLY EXPECTING MODERATE TO HEAVY RAIN MULTICELLULAR STORMS CAUSING NUISANCE/SMALL STREAM FLOODING AT THIS TIME. SEE HYDRO SECTION FOR MORE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 333 PM MDT MON AUG 18 2014 THE FORECAST AREA REMAINS UNDER SW FLOW WED-THU WITH THE JET AXIS OVERHEAD. MONSOONAL MOISTURE PLUME WEAKENS WITH PRECIPITABLE WATER VALUES DROPPING UNDER 1 INCH. NAM/GFS SHOW A WEAK 300 MB JET MAX ARRIVING ON WED FOR POTENTIAL SUPPORT AND INCREASED VERTICAL SHEAR....AND SHOULD IT ENTRAIN SOME DRIER MIDLEVEL AIR OVER HIGHER MOISTURE NEAR THE SURFACE...IT COULD LEAD TO SOME STRONGER STORMS WED AFTERNOON. MODELS STILL HAVING TROUBLE HANDLING THE UPPER LOW THAT IS CURRENTLY DROPPING SOUTH ALONG THE NRN CA COAST...WHICH LOWERS FORECAST CONFIDENCE AFTER MIDWEEK. BUT AT LEAST THE GFS AND ECWMF NOW BOTH BRING THE 500 MB LOW INLAND...JUST TIMING AND TRACK ARE DIFFERENT. THE 12Z GFS SWINGS THE LOW INLAND ACROSS SRN CA WED AND THEN LIFTS IT NE ACROSS UT AS AN OPEN WAVE ON THU. THIS COULD ADD SOME DYNAMIC PUNCH TO STORM DEVELOPMENT ON THU. THE 12Z ECMWF IS SLOWER BRINGING IT INLAND AND TRACKS IT FARTHER SOUTH ACROSS AZ AND NWRN NM. THE 12Z CANADIAN HAS IT SHEARING OUT ALONG THE SRN CA COAST THU-FRI. MODELS ALSO SHOW ENERGY DROPPING OUT OF THE GULF OF AK LATE IN THE WEEK THAT SHOULD MAINTAIN TROUGHING OVER THE PAC NW/NRN ROCKIES. FOR NOW...WITH FOLLOW THE CONSENSUS MODEL TREND...WHICH SHOWS A LESSENING OF STORM COVERAGE THE LAST HALF OF THE WEEK BUT NOT A COMPLETE CESSATION. LOWER LEVEL MOISTURE LIKELY TO LINGER WITH SOME SMALLER EMBEDDED WAVES IN THE FLOW THAT COULD TRIGGER ISOLATED- SCATTERED ACTIVITY ABOUT EACH DAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1057 PM MDT MON AUG 18 2014 PLENTY OF CONVECTION CONTINUES THIS MORNING WITH SHOWERS AND OCCNL RUMBLES OF THUNDER. THIS WILL LIKELY CONTINUE THROUGH 09Z WITH A SLIGHT DOWNTICK AFTER THAT. SHOWERS AND STORMS WILL PICK UP AGAIN WITH HEAVY RAIN...HAIL...AND GUSTY OUTFLOW WINDS OVERSPREADING THE AREA FROM NOON ONWARDS WITH WIDEST COVERAGE FROM 21Z ONWARDS. IFR/MVFR MAY OCCUR OVER AERODROMES DUE TO HEAVIER SHOWERS DROPPING VIS AND ALSO DROPPING CIGS. MODELS CONTINUE PRECIP OVERNIGHT SO EXPECT THESE CONDITIONS TO PERSIST THROUGH 06Z TOMORROW. MTN OBSCURATIONS WILL ALSO BE COMMON. && .HYDROLOGY... ISSUED AT 333 PM MDT MON AUG 18 2014 MONSOONAL MOISTURE WILL RETURN TOMORROW AS AN UPPER LEVEL LOW OVER CALIFORNIA PULLS DEEP SUBTROPICAL MOISTURE INTO THE REGION. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE FROM WEST TO EAST THROUGHOUT THE AFTERNOON AND PEAK DURING THE LATE HOURS OF THE DAY AND OVERNIGHT INTO WEDNESDAY MORNING. EXPECTING TO HAVE SMALL STREAM AND ARROYO FLOOD ISSUES BY WEDNESDAY MORNING IN THE USUAL PROBLEM AREAS...BUT AT THIS NOT EXPECTING HIGH COVERAGE OF TORRENTIAL DOWNPOURS DUE TO THUNDERSTORMS. THEREFORE...NO WATCHES HAVE BEEN ISSUED AT THIS TIME. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JAM LONG TERM...JAD AVIATION...TGR HYDROLOGY...JAM
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
116 AM EDT TUE AUG 19 2014 .PREV DISCUSSION... /ISSUED 936 PM EDT MON AUG 18 2014/ UPDATE... HAVE MADE SEVERAL CHANGES TO POPS THROUGH THE EVENING TO ACCOUNT FOR TRENDS. MOST CONVECTION IS DYING OFF NOW...WITH ONLY LIGHT RAIN REMAINING...BUT THE LEFTOVER MISSISSIPPI VALLEY MCV IS WORKING ITS WAY ACROSS NORTHERN ALABAMA AT AFD TIME AND SHOULD PUSH INTO NORTH GEORGIA IN THE NEXT FEW HOURS. AGAIN HAVE TRIED TO ADJUST POPS TO ACCOUNT FOR THIS. AIRMASS IS PRETTY STABLE BEHIND CONVECTION THIS EVENING SO THINK SEVERE POTENTIAL WITH ANY MCV CONVECTION WOULD BE PRETTY LOW...HEAVY RAIN WOULD BE THE MORE SIGNIFICANT THREAT. UPDATED PRODUCTS OUT SHORTLY. TDP PREV DISCUSSION... /ISSUED 750 PM EDT MON AUG 18 2014/ PREV DISCUSSION... /ISSUED 320 PM EDT MON AUG 18 2014/ SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... STALLED FRONTAL BOUNDARY STRETCHES FROM THE TN VALLEY TO THE SOUTHERN MID ATLANTIC STATES. A HIGH PRESSURE RIDGE IS SITUATED ACROSS NORTHERN FL. 500MB ANALYSIS AND WV LOOP SHOWS A POTENT SHORTWAVE MOVING EAST ACROSS NORTHERN MS. THIS FEATURE WILL BE THE FOCUS FOR LATE AFTERNOON AND EVENING CONVECTION ACROSS THE CWFA. THE 16Z HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION THIS AFTERNOON. HAVE TRIED TO ORIENT THE POPS ACCORDING TO CURRENT RADAR TRENDS AND CLOSE TO THE HRRR SOLUTION. GOOD INSTABILITY DOES EXIST AT THE SURFACE...BUT LAPSE RATES REMAIN POOR UNTIL THE COLD POOL ALOFT MOVES OVERHEAD. BY THE TIME THE SHORTWAVE NEARS THE CWFA...INSTABILITY HAS DECREASED WITH THE LOSS OF HEATING. HOWEVER...WITH UNIDIRECTIONAL FLOW...STORMS MAY MOVE REPEATEDLY OVER THE SAME AREAS...WITH LOCALLY HEAVY RAINFALL POSSIBLE. AREAS TO THE NORTH RECEIVED ONE TO TWO INCHES OF RAINFALL OVERNIGHT/EARLY THIS MORNING...SO ANY TRAINING STORMS OR HEAVY RAINFALL MAY CAUSE SOME LOCALIZED FLOODING. BY EARLY TUESDAY...THE POTENT EVENING/OVERNIGHT SHORTWAVE WILL HAVE MOVED OFF TO THE EAST. MODELS ARE PROGGING ANOTHER...WEAKER... SHORTWAVE TO MOVE EAST IN THE FLOW TOMORROW. CONFIDENCE IS LOW ON EXACTLY WHERE CONVECTION WILL DEVELOP TOMORROW. NLISTEMAA LONG TERM /WEDNESDAY THROUGH MONDAY/... LONG TERM FORECAST IS ON TRACK AND HAVE NOT MADE SIGNIFICANT ADJUSTMENTS. ONE ADDITIONAL POINT TO NOTE IS THAT HEAT INDEX VALUES ARE CREEPING ABOVE 100 DEGREES SOUTH OF AN ATLANTA TO ATHENS LINE...WITH PORTIONS OF CENTRAL GEORGIA APPROACHING 105 DEGREES DURING THE SECOND HALF OF THE WEEK. IF THIS TREND CONTINUES...MAY NEED A HEAT ADVISORY FOR THESE 105-108 DEGREE VALUES ACROSS THE SOUTHEAST PART OF THE CWA. 11/ATWELL LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... 00Z GFS AND ECMWF ARE IN UNCOMMONLY GOOD AGREEMENT THROUGH THE EXTENDED FORECAST PERIOD AND CONTINUE THE RECENT TREND OF BUILDING UPPER-LEVEL HIGH PRESSURE INTO THE CENTRAL GULF COAST REGION AND LOWER MISSISSIPPI VALLEY FROM MID-WEEK THROUGH NEXT WEEKEND. BY THE WEEKEND THE UPPER RIDGE IS QUITE STRONG...BUT GEORGIA REMAINS ON THE EASTERN PERIPHERY. THIS SHOULD ALLOW VERY WARM TEMPERATURES AND INHIBIT DIURNAL CONVECTION SOMEWHAT...BUT I DO NOT BELIEVE THE FORECAST AREA IS CLOSE ENOUGH TO THE CENTER OF THE RIDGE TO ELIMINATE POPS ALTOGETHER. 20 && .AVIATION... 06Z UPDATE... POTENTIAL FOR INCREASING LIFR-MVFR CEILINGS ACROSS THE TAF SITES WITH SOME MVFR VSBYS DUE TO FOG. IMPROVEMENT EXPECTED TO VFR DURING THE LATER MORNING. POTENTIAL FOR SHOWERS AND THUNDERSTORMS ALMOST ANY TIME TODAY. SURFACE WINDS LIGHT WSW INCREASING TO MAINLY WEST AROUND 10 KTS WITH SOME GUSTS AROUND 20 KTS. //ATL CONFIDENCE...06Z UPDATE... LOW CONFIDENCE ON CEILINGS/VSBYS AND IMPACTS OF THUNDERSTORMS TODAY. HIGH CONFIDENCE ON WINDS. BDL && .PRELIMINARY POINT TEMPS/POPS... ATHENS 91 72 97 72 / 40 30 10 5 ATLANTA 88 73 94 75 / 40 30 10 5 BLAIRSVILLE 84 67 90 68 / 40 30 20 10 CARTERSVILLE 89 71 94 71 / 40 30 10 5 COLUMBUS 92 73 96 75 / 40 30 10 5 GAINESVILLE 89 71 94 73 / 40 30 10 10 MACON 92 72 97 74 / 40 30 10 5 ROME 89 71 95 71 / 40 30 20 10 PEACHTREE CITY 89 71 94 72 / 40 30 10 5 VIDALIA 95 74 97 76 / 40 30 20 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BDL LONG TERM....20 AVIATION...BDL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
106 AM CDT TUE AUG 19 2014 .DISCUSSION... 650 PM...EARLY EVENING UPDATE...CONVECTION FIRING ACROSS CENTRAL WI WILL CONTINUE THIS EVENING WITH ADDITIONAL THUNDERSTORMS RAPIDLY DEVELOPING OVER FAR NORTHERN IA AND SOUTHERN MN. THIS ACTIVITY WILL SLOWLY SAG SOUTH BUT PROBABLY NOT REACH NORTHERN IL UNTIL AFTER 04Z-05Z. ACTIVITY WILL THEN SPREAD SOUTHEAST ACROSS MAINLY THE NORTHERN TWO THIRDS OF THE CWA OVERNIGHT. SHORT TERM/ HI RES GUIDANCE IS IN FAIR AGREEMENT WITH MUCH OF THE AREA NOW STAYING DRY THROUGH MIDNIGHT. HAVE UPDATED GRIDS/ZFP FOR THESE TRENDS ALONG WITH MOSTLY CLEAR SKIES OVER MUCH OF THE AREA AS CU FIELD DISSIPATES...THOUGH HIGH CLOUDS WILL LIKELY QUICKLY SPREAD ACROSS THE AREA LATER THIS EVENING AS STORMS APPROACH. NO CHANGES TO LIKELY POPS OVERNIGHT THOUGH POPS MAY NEED TO BE LOWERED ACROSS THE FAR SOUTH AS TRENDS EMERGE. CMS //PREV DISCUSSION... 239 PM CDT SYNOPSIS...A WARMER AND NOTICEABLY MORE HUMID PATTERN WILL BE DEVELOPING THROUGH MID WEEK. IN ADDITION TO THE WARMTH AN EVOLVING UPPER AIR PATTERN WILL BRING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND. HIGH TEMPERATURES LATER IN THE WEEK MAY BE DICTATED BY THE CONVECTION. TONIGHT... A LOW PRESSURE TROUGH IS OVER MINNESOTA AND IT WILL BECOME A CLOSED LOW OVER WISCONSIN AND LAKE SUPERIOR TUESDAY EVENING. AT THE SURFACE THERE IS A LOW PRESSURE TROUGH OVER MINNESOTA THAT WILL BECOME A CLOSED LOW OVER WISCONSIN TOMORROW MORNING. THE LOW WILL PUSH EAST OF THE LAKE WEDNESDAY. EXPECTING THE FIRST ROUND OF STORMS TO MOVE INTO THE RFD AREA THIS EVENING WITH THE MAJORITY OF CONVECTIVE ACTIVITY REMAINING OVER WISCONSIN CLOSER TO THE LOW. THE FIRST WAVE WILL WEAKEN AS IT PUSHES EAST. A SECOND WAVE FORMS AHEAD OF A VORT STREAMER OVERNIGHT AND THINKING THIS WILL BE THE MAIN SHOW TONIGHT. EXPECTING ACTIVITY TO REMAIN NORTH OF I-80 MOST OF THE NIGHT. ACTIVITY WILL THEN SPREAD SOUTH AND EAST COVERING AREAS EAST OF I-39 EARLY TUESDAY MORNING. THIS ACTIVITY WILL WEAKEN THROUGH THE MORNING AND CONTINUE SOUTHEAST OUT OF THE WARNING AREA. THE FIRST CONCERN OVERNIGHT IS HEAVY RAIN AS PWAT VALUES WILL BE BETWEEN 1.5 AND 1.75 INCHES. CAPE VALUES WILL BE AROUND 1000 J/KG THIS EVENING AND THEN DIMINISH OVERNIGHT. SHEAR VALUES ARE 20-30 KT SO SEVERE WEATHER IS NOT EXPECTED...BUT SMALL HAIL MAY OCCUR WITH THE STRONGEST STORMS. STEERING LEVEL FLOW IS ALSO WEAK SO STORMS WILL BE SLOW MOVING WHICH COULD ENHANCE RAINFALL TOTALS. THE OTHER CONCERN IS FOG TONIGHT. IF WE CLEAR OUT AT ALL EXPECTING AREAS OF DENSE FOG TO DEVELOP. HAVE MEDIUM CONFIDENCE IN SKY COVER SO ONLY HAVE PATCHY FOG IN THE FORECAST TONIGHT AFTER MIDNIGHT. TUESDAY AND TUESDAY NIGHT... MORE STORMS ARE EXPECTED AS THE LOW SHIFTS EAST OVER WISCONSIN. EXPECTING FOG/LOW STRATUS/GENERAL CLOUD COVER TO THIN TUESDAY MORNING. HEATING WILL RESULT IN DECENT CAPE VALUES. THE MOISTURE RICH NAM FEATURES THE HIGHEST CAPE VALUES AROUND 3000 J/KG BUT THE MORE CONSERVATIVE GFS ONLY SHOWS LESS THAN 1000 J/KG. SHEAR VALUES STILL LOOK MARGINAL AROUND 35 KT. BUT PWAT VALUES WILL BE A BIT LOWER AT 1.3 TO 1.5 INCHES. HEAVY RAIN IS STILL POSSIBLE BUT STORMS SHOULD BE MOVING AT A BETTER PACE WITH STRONGER STEERING LEVEL FLOW. THE FORCING WILL BE A COMBO OF THE LOWS FRONT THAT MOVES THROUGH IN THE LATE AFTN/EVENING AND VORTICITY STREAMERS THAT ROTATE AROUND THE LOW. HAVE MEDIUM CONFIDENCE IN WIDESPREAD TS COVERAGE...BUT KEPT POPS IN THE CHANCE RANGE DUE TO LOW CONFIDENCE IN WHEN AND WHERE STORMS WILL DEVELOP. HAIL AND STRONG WINDS ARE POSSIBLE IN ADDITION TO THE HEAVY DOWNPOURS. TEMPS REMAIN A CHALLENGE AS WE COULD BE WARMER IF SKY COVER IS ON THE WEAKER SIDE. HOWEVER...HAVE MEDIUM CONFIDENCE IN WIDESPREAD TS COVERAGE SO KEPT HIGH TEMPS IN THE LOW TO MID 80S. JEE WEDNESDAY THROUGH SUNDAY... THE UPPER LOW OVER THE UPPER GREAT LAKES WILL START TO MOVE MORE QUICKLY TO THE NORTHEAST WEDNESDAY MORNING AS NORTHERN PACIFIC TROUGHING PUSHES INLAND OVER WESTERN CANADA. THIS HELPS TO PUSH CUTOFF LOW PRESSURE ONTO THE CALIFORNIA COAST WITH BOTH OF THESE FEATURES HELPING TO DRIVE UPPER RIDGE DEVELOPMENT OVER THE HIGH PLAINS. THE LOCAL AREA WILL BE BETWEEN THE DEPARTING UPPER LOW AND THE APPROACHING RIDGE WEDNESDAY MORNING WITH WEAK LOW LEVEL FLOW IN PLACE AS WELL. THIS SHOULD RESULT IN DRY WEATHER FOR MUCH OF WEDNESDAY BEFORE MID LEVEL BAROCLINICITY INCREASES LATE IN THE DAY AND MORE SO IN THE EVENING AS THE RIDGE APPROACHES. PRECIPITABLE WATER VALUES WILL INCREASE MARKEDLY WITH THE ARRIVAL OF THE MID LEVEL WARM ADVECTION LEADING TO MOIST ASCENT WEDNESDAY EVENING AND WEDNESDAY NIGHT. THIS LIFT ALONE MAY BE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS AND MAY BE AIDED BY THE PASSAGE OF AN UPPER WAVE WHICH GUIDANCE HAS BEEN HINTING AT. THIS IS CERTAINLY PLAUSIBLE GIVEN THE PRESENCE OF THE DEEP TROUGH TO THE WEST AND THE TENDENCY FOR WAVES TO EMANATE FROM IT. WILL CARRY HIGHEST POPS LATE WEDNESDAY EVENING THROUGH THURSDAY MORNING. THE RIDGE AXIS WILL SHIFT EASTWARD ACROSS THE AREA THROUGH FRIDAY. THE AMPLITUDE OF THE RIDGE AND THEREFORE THE POSITIONING OF THE TRACK OF SHORTWAVES/THUNDERSTORMS ALONG ITS NORTHERN PERIPHERY WILL BE DRIVEN BY THE SPEED WITH WHICH THE LARGE WESTERN UPPER TROUGH EVOLVES EASTWARD. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE TROUGH AND THEREFORE SHARPER WITH THE RIDGE SUGGESTING THAT THE MAIN STORM TRACK WILL BE NORTH OF THE LOCAL AREA FRIDAY WHEREAS THE SLOWER AND LOWER AMPLITUDE ECMWF KEEPS THE FAVORED TRACK ACROSS THE AREA INTO THE WEEKEND. THE UPPER TROUGH WILL EVOLVE EASTWARD PUSHING THE RIDGE TO THE EAST AND BRINGING A COOL FRONT INTO THE REGION LATE IN THE WEEKEND. THE BIGGEST UNCERTAINTY IS THE TIMING. WITH PRECIPITABLE WATER VALUES OVER 2 INCHES FROM THURSDAY ONWARD HEAVY RAINFALL WILL BE A CONCERN WITH ANY STORMS...ESPECIALLY IF MULTIPLE ROUNDS ARE ABLE TO AFFECT THE AREA THROUGH THE WEEKEND. HOWEVER A SHARPER RIDGE WOULD RESULT IN A SHIFT IN THE TRACK TO THE NORTH AND STRONGER CAPPING LOCALLY. TEMPERATURES WILL BE WARMING INTO THE MID 80S WEDNESDAY AND MOSTLY MID AND UPPER 80S FROM THURSDAY INTO THE WEEKEND. LAKESHORE AREAS WILL LIKELY BE COOLER MOST DAYS WITH LAKE INFLUENCES EXPECTED DUE TO A RATHER LIGHT LOW LEVEL FLOW. THUNDERSTORMS AND ANY REMNANT INFLUENCES MAY NEGATIVELY AFFECT HIGHS DEPENDING ON THEIR TIMING. CANNOT RULE OUT SOME 90 DEGREE READINGS IN THE WEST AND SOUTH LATE IN THE WEEK...ESPECIALLY IF THUNDERSTORM ACTIVITY KEEPS AT A MINIMUM. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * A PERIOD OF SHRA/TSRA POSSIBLE SOMETIME BETWEEN 08Z-11Z. * POTENTIAL FOR LOWER CIGS LATE TONIGHT INTO TUE MORNING. * CHANCE FOR SCATTERED SHRA/TSRA MUCH OF TUE WITH A SLIGHTLY MORE FAVORED TIME DURING THE AFTERNOON. KREIN //DISCUSSION...UPDATED 06Z... A QUIET EVENING IS EXPECTED OVER LOCAL AIRPORTS BEFORE TSRA CHANCES INCREASE OVERNIGHT. AN UPPER LEVEL DISTURBANCE MOVING EAST THROUGH WISCONSIN CONTINUES TO GENERATE A LINE OF THUNDERSTORMS EXTENDING FROM NEAR OSHKOSH SOUTHWEST TO NEAR DES MOINES ALONG A WEAK COLD FRONT...WITH AN ADDITIONAL CLUSTER OF SHOWERS AND EMBEDDED THUNDERSTORMS RIGHT UNDER THE MAIN UPPER CIRCULATION CENTER. LATEST TRENDS INDICATE THAT THE UPPER LEVEL SYSTEM IS TRACKING ALMOST DUE EAST WHILE THE MAIN CONVECTIVE LINE SLOWLY SAGS SLIGHTLY SOUTH OF EAST. HAVE DECREASING CONFIDENCE IN THE POTENTIAL FOR ANY OF THE TS TO REACH ANY OF TERMINALS EXCEPT FOR ROCKFORD. ALSO...THE LATEST MODEL GUIDANCE IS SHOWING THAT STEERING FLOW IS TURNING MORE DUE WESTERLY AS THE UPPER SYSTEM MOVES EWD...WHICH WOULD THEN CAUSE THE SOUTHERN END OF THE CONVECTIVE LINE TO STRETCH OUT IN A MORE EAST-WEST ORIENTATION NEAR THE IL/WI BORDER. HOWEVER...THERE IS STILL SOME DEVELOPMENT ALONG THE SRN END OF THE LINE OVER NERN IA INTO CNTRL IA...SO CONFIDENCE IS NOT HIGH ENOUGH TO PULL THE TS FROM THE TAFS FOR THE LATE NIGHT HOURS AS THERE IS STILL SOME MOISTURE TRANSPORT AND BROAD SCALE LIFT OVER NRN IL WHERE 850MB WINDS ARE STILL WSWLY. ANOTHER FACTOR POINTING TO A LOWER TS POTENTIAL IS THE LACK OF STRONG SFC FORCING AND THAT THE SYSTEM IS ALMOST ENTIRELY RELYING ON UPPER LEVEL FORCING. SO...TO MAKE A SHORT STORY LONG...WILL MAINTAIN THE TS IN THE TAFS BTWN 08-11Z...AND REFINE THE FORECAST WHEN CONFIDENCE IS A LITTLE HIGHER. WHAT THUNDER THAT DOES MANAGE TO MOVE SOUTH OF THE WISCONSIN BORDER SHOULD DISSIPATE BEFORE DAYBREAK...BUT WITH A MOIST AIRMASS IN PLACE AND THE MAIN SYNOPTIC SCALE UPPER LOW MOVING OVER NRN WISCONSIN BY MID DAY TUESDAY...THERE WILL STILL BE ADEQUATE CYCLONIC FLOW ALOFT THAT SCT SHRA AND ISOLD TSRA COULD STILL DEVELOP DURG THE DAYTIME HOURS. CHANCES FOR MORE ORGANIZED TS WILL INCREASE THROUGH THE AFTERNOON AS ANOTHER MID LEVEL IMPULSE TRACKS AROUND THE SRN PERIPHERY OF THE MAIN UPPER LOW. AS FOR WINDS...LIGHT SWLY WINDS WILL CONTINUE IN ADVANCE OF THE WEAK COLD FRONT...AND INCREASE THROUGH THE MORNING AS THE SFC PRESSURE GRADIENT STRENGTHENS. BY LATE MORNING...SWLY WINDS SHOULD INCREASE TO 10-15KT WITH OCNL GUSTS OF 15-20KT PERSISTING THROUGH EARLY EVENING WHILE GRADUALLY VEERING TO WESTERLY BY LATE AFTERNOON. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW CONFIDENCE IN TIMING AND COVERAGE OF TS ASSOCIATED WITH THE COLD FRONT AND THE DIRECT IMPACT ON THE TERMINALS. * MEDIUM TO HIGH CONFIDENCE IN WIND SPEED AND DIRECTION...THOUGH THE WIND FIELD COULD BE LOCALLY DISRUPTED BY ANY TS THAT DO DEVELOP. * LOW IN MVFR CIGS OCCURRING LATE TONIGHT INTO TUE MORNING. * LOW IN WHETHER TSRA OCCURS TUESDAY AND IN SPECIFIC TIMING. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...CHANCE OF TSRA AND LOWER CIGS DURING THE NIGHT. THURSDAY-SATURDAY...PERIODS OF TSRA POSSIBLE. SUNDAY...SLIGHT CHANCE OF TSRA. MTF && .MARINE... 239 PM CDT LOW PRESSURE OVER MINNESOTA WILL MOVE OVER WISCONSIN TOMORROW AND THEN OVER THE LAKE TOMORROW EVENING AND NIGHT. WINDS WILL BECOME SOUTH ACROSS THE LAKE AND INCREASE TO 15 TO 25 KT OVERNIGHT. AS THE LOW MOVES OVER THE LAKE TOMORROW...WINDS WILL DIMINISH SLOWLY OVER THE SOUTH HALF AND BECOME SW. ON THE NORTH HALF...WINDS WILL ALSO DIMINISH AND BECOME SE TO E AHEAD OF THE LOW. THE LOW SHIFTS EAST OF THE LAKE TUESDAY NIGHT AND WINDS BECOME NW 10-15 KT. THE LOW SHIFTING TO THE EAST WILL LEAVE A WEAK PRESSURE GRADIENT IN ITS WAKE. THIS WILL RESULT IN LIGHT ONSHORE OR VARIABLE WINDS WEDNESDAY WITH BEFORE A SOMEWHAT BETTER ORGANIZED PRESSURE GRADIENT SPREADS IN WITH LOW PRESSURE FROM THE CENTRAL HIGH PLAINS TO NORTHERN MANITOBA. THIS WILL BRING MAINLY SOUTH TO SOUTHEAST WINDS ACROSS THE LAKE THURSDAY...WITH OCCASIONAL EAST WINDS OVER THE FAR NORTH...BUT EVEN THEN THE FLOW MAY BE WEAK ENOUGH TO SUPPORT A SHIFT TO ONSHORE WINDS THURSDAY AFTERNOON. SOUTH TO SOUTHEAST WINDS ARE FAVORED THROUGH THE WEEKEND BUT THERE MAY BE QUITE A BIT OF VARIABILITY IF THE LOW PRESSURE TO THE WEST EVOLVES MORE SLOWLY AS SOME FORECAST GUIDANCE INDICATES. THE UPPER FLOW PATTERN DOES LOOK TO SHIFT SUNDAY OR MONDAY BRINGING A COOL FRONT ACROSS THE LAKE WITH A SHIFT TO NORTHERLY WINDS WHICH MAY BE RATHER BREEZY. JEE/MDB && .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 1152 PM CDT Mon Aug 18 2014 .UPDATE... ISSUED AT 900 PM CDT MON AUG 18 2014 Skies have become mostly clear across central and SE Illinois this evening as diurnal heating ends. Although a few pockets of light fog are possible early tonight, the next main forecast feature will be the chance for thunderstorms overnight as an upper level shortwave and cold front move into central IL. Have trimmed back POPs before midnight as current radar and satellite indicate storms are still several hours away. HRRR model simulated reflectivity has been depicting movement of the system well in northern IA, southern MN, southwest WI this evening and has been used as a guide for timing through the first few hours of Tuesday. Currently the system is associated with a slight risk (15% +) of severe winds and hail to our northwest, but as it approaches central IL, CAPE of 3000 J/kg should be diminishing to around 1500 or less with marginal 0-6 km bulk shear around 25-30 kts. This is enough for only a 5% severe risk from the Illinois River northwest. To the south, risk of severe storms is negligible, but at least a slight chance for storms will reach as far as SE Illinois by early morning. Have sent updates for POP/Temp/Humidity/Wind trends this evening/early tonight. && .SHORT TERM...(This evening through Tuesday) ISSUED AT 311 PM CDT MON AUG 18 2014 Earlier stratus has given way to diurnal type clouds over central and southeast Illinois early this afternoon, underneath a weak high pressure axis. Leading edge of shortwave currently seen on water vapor imagery pushing through Minnesota and northern Iowa, with a more potent vorticity maximum moving out of North Dakota. Convection ahead of the shortwave expected to begin over the next couple hours over northern Iowa, where skies have been sunny and CAPE`s are over 3000 J/kg per SPC mesoanalysis. High-resolution models pushing the first wave of storms into Wisconsin with another line forming in southern Minnesota/northern Iowa later this evening. The second line is more of a concern for us as it will have a southeast trajectory. However, most of the models show some fading of the line with more of the energy staying to our north, and a separate convective cluster developing over northwest Missouri overnight. Have adjusted the PoP`s in our area to be primarily after midnight, and largely eliminated them south of I-70. Associated surface boundary expected to push into central Illinois Tuesday afternoon as the upper wave arrives. Some concerns with severe weather potential across east central and southeast Illinois, as development takes place early afternoon and bulk shear increases during the peak heating time. Latest Day2 SPC convective outlook indicates a severe threat southeast of a Danville to Effingham line, with NAM indicating a 2 pm to 7 pm time frame being the most concern. && .LONG TERM...(Tuesday night through Monday) ISSUED AT 311 PM CDT MON AUG 18 2014 Tuesday evening will see decreasing storm chances from north to south as a shortwave in the upper level trough over the Great Lakes advances east of IL. We are in the day 2 slight risk in our southeast counties, so we can`t rule out some lingering strong storms into early evening, but the main threat should advance southeast of IL by mid evening. Additional storm chances re-develop across our far S-SW counties late Tue night as a 300mb 75kt jet max in the back side of the trough generates some lift in the left exit region. Minor rain/storm chances will continue on Wednesday as the jet max progresses eastward over Illinois, but only slight chances are expected. Wednesday night, a warm front developing across our northern counties oriented from NW to SE will become a focus for a round of storms, with chances increasing to likely after midnight along and north of I-74. Storms should progress northward with the warm front on Thursday. However, storms chances are expected to linger north of a line from Peoria to Paris Thursday and Thursday night. Height rises and mid-level warming on Friday and Saturday should help to keep provide a capping layer, and reduce storm chances across central IL. The may be an isolated late afternoon or early evening flare-up of a storm, but most areas should stay dry. Rain-free conditions are forecast to continue into Sunday by the ECMWF and GFS. They both show a cold front arriving later Sunday night and wash-out as it passes across IL on Monday. The weakening front is not expected to trigger much in the way of storms at this point, but confidence is low on that scenario staying dry. Heat and humidity will definitely dominate the last half of this week, as highs climb into the upper 80s and lower 90s, with heat index readings in the mid to upper 90s. Some relief will come on Monday behind the cold front, with low to mid 80s for highs and lowering dewpoints into the 60s. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 1152 PM CDT MON AUG 18 2014 Patchy fog resulting in VLIFR to MVFR conditions in place from around K1H2-KAAA-KCMI eastward, with a line of thunderstorms approaching northern IL from the northwest. Fog expected to dissipate as light SSW winds ahead of the line of thunderstorms promotes mixing. This line expected to weaken as it approaches and mainly affect TAF sites from KPIA and KBMI northward. Have included VCTS in central IL TAFs to address potential for thunderstorms, but likelihood of MVFR conditions looks too low for explicit mention at this time. A break in shower/thunderstorm activity likely in the morning, then an upper level shortwave and daytime heating should produce a re- intensification of storms along the cold frontal boundary lingering over central Illinois. Have brought VCTS and ceilings near MVFR thresholds for the remainder of the afternoon to account for this. Starting around 00Z, conditions expected to improve as frontal boundary and upper level shortwave moves east of the area. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ONTON SHORT TERM...GEELHART LONG TERM...SHIMON AVIATION...ONTON
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1235 AM CDT Tue Aug 19 2014 ...Updated for Aviation... .SHORT TERM...(This evening through Tuesday) ISSUED AT 1202 PM CDT MON AUG 18 2014 There is a high pressure ridge over Colorado south into New Mexico late this afternoon. A lee side trough is near the Kansas and Colorado border, and a warm front has been pushing northeast through western Kansas this morning. The forecast is on track for today, with highs just over 100F degrees likely somewhere across southern and western Kansas, and upper 90s in our northern zones. There could be a few and far between showers and isolated thunderstorms just about anywhere late today. The HRRR model shows a few thunderstorms across our south and southeast zones after 21z, but the NAM and NAMNG5 models are showing storms first over our west and then moving across the northern CWA. Mid and high clouds will be on the increase late this afternoon and evening. So, the low Pops in the 17-20 percent range blanketing our forecast area seem reasonable. Time will tell on which model is more correct. The same HRRR, NAM, and NAMNG5 models decrease the measurable precip after 04Z, and then the clouds will slowly dissipate after 09Z or so. I plan to reduce 20 percent Pops rapidly between 06Z and 12Z. Not much precipitation will fall either, as any convection will be high based. I used the QPF_from_PoP application, and it only shows 0.01 to spotty 0.03 inches of rain overnight. With clouds breaking late and perhaps a little rain, minimum temperatures should end up in the middle 60s in Syracuse, Scott City, and Wakeeney, while settling only to around 70F degrees in the Meade, Coldwater and Medicine Lodge areas. Winds will continue to hover at less than 10 MPH tonight. On Tuesday, the surface low will advect into central Kansas, and the front will sag south across part of our CWA. Thus, Max temps should dip just a little north of the front, while south along the Oklahoma border near Medicine Lodge, it should warm up to around 100F. Winds on Tuesday will be breezy from the south in the 15 to 25 mph and gusty range. I do not think there will any precipitation on Tuesday, as the lower max temps will result in less instability than today. .LONG TERM...(Tuesday night through Monday) ISSUED AT 225 PM CDT MON AUG 18 2014 Medium range models indicate an upper level ridge of high pressure transitioning eastward out of the Western High Plains into the Central Plains to begin the period Tuesday night. Combined with a weak flow aloft, drier conditions are likely to prevail through late Wednesday afternoon. Meanwhile, an upper level trough will dig southeast across southern California Wednesday setting up a strong southwest flow aloft across the Central and Southern Rockies, including a +90kt jet core projected to lift northeast out of the Desert Southwest into the Colorado Rockies. With a prevailing lee side trough providing increased convergence in the lower levels, thunderstorm development is likely across portions of eastern Colorado Wednesday afternoon with a few storms potentially drifting into western Kansas later in the evening through early Thursday. However, the weaker flow aloft across western Kansas will limit the strength and coverage of any storms. The upper level shortwave will then lift northeast going into the weekend while a large scale upper level high remains locked in across the Deep South. Although precip chances will remain present virtually each day into the weekend, the weaker flow aloft will limit storm development, strength, and coverage. Temperatures will remain above normal Wednesday as the aforementioned upper level ridge shifts east across the Central Plains. A prevailing southerly flow across western Kansas will reinforce the warmer air mass already in place across the region with H85 temperatures ranging from the upper 20s(C) in central Kansas to around 30C closer to the Colorado border. As lower level lapse rates steepen into the afternoon, look for highs well up into the 90s(F) to near 100F Wednesday. Similar temperatures are then expected each day through Saturday as the low level southerly flow persists into the early part of the weekend. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 1232 AM CDT TUE AUG 19 2014 A few showers and isolated thunderstorms will dissipate by 07-09Z this morning. A lee trough of low pressure will deepen with south winds increasing to 15-25kt after 18Z. VFR conditions are expected. && .PRELIMINARY POINT TEMPS/POPS... DDC 71 99 74 100 / 0 10 10 10 GCK 70 98 70 100 / 0 10 10 10 EHA 69 98 68 97 / 10 20 20 20 LBL 70 98 71 100 / 0 10 10 10 HYS 71 99 73 98 / 0 10 20 20 P28 74 99 76 100 / 0 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Burke LONG TERM...JJohnson AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1136 PM CDT Mon Aug 18 2014 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Tuesday) Issued at 352 PM CDT MON AUG 18 2014 The center of an upper level trough was located across eastern ND late this afternoon with an upper level trough axis extending southwest across central SD. The numerical models show this upper level trough digging southeast across southern MN and eastern NE into northern MO. The southwest section of the upper trough will move southeast across northeast KS between 6Z and 12Z. The NAM, GFS and ECMWF forecast QPF across northeast and east central KS later Tonight, with the ECMWF and NAM showing most of the CWA with QPF. The NAM model shows weak isentropic lift at the 310K level with LFCs around 700mb. The most intense isentropic lift at the 310K level will be across northern MO and IA. The mesoscale models, consisting of the ARW, NMM and HRRR do not forecast any QPF across the CWA tonight. I will probably keep slight chance to chance pops across much of the CWA, since the ascent ahead of the H5 trough combined with isentropic lift should allow elevated thunderstorms to develop across the northeast counties of the CWA around midnight, then building southwest across the central and southwest counties of the CWA through the early morning hours before spreading southeast across much of east central KS by 12Z TUE. Any lingering elevated thunderstorms, if they do develop, will shift southeast of the CWA during the mid morning hours. Skies should clear through the late morning and early afternoon hours and temperatures will warm into the lower to mid 90s. If there is a leftover outflow boundary across the northeast counties, then temperatures along the NE border may only reach into the upper 80s. I placed in 14 pops in case there is enough surface convergence for an isolated thunderstorm during the afternoon hours. .LONG TERM...(Tuesday Night through Monday) Issued at 352 PM CDT MON AUG 18 2014 Models are in agreement that heights rises and resulting warm air advection will be situated across the northeast corner of the county warning area Tuesday evening providing another chance for thunderstorms. As this area focuses further northward through the night...have removed pops this area after midnight. Will keep lows mild in the low to middle 70s. This will then set the stage for mostly sunny very warm...breezy day on Wednesday. Highs will generally be 95 to 100 degrees with the warmest in the Abilene area and the coolest near Hiawatha. As the upper ridge builds across the southern plains...expect dry weather across the cwa Wednesday night through Thursday. However... with south winds continuing...highs Thursday will again be in the middle to upper 90s. As the cutoff upper trough in the desert southwest gets picked up by Thursday and heads into the central and northern high plains into the weekend...there will be better chances for thunderstorms across the area...although the northern/northwest 1/2 of the cwa will be the more likely areas to see rain. Do not expect a frontal passage until during the day Sunday...so may not see highs temps below 90 degrees until Monday when readings in the middle to upper 80s should be the rule. && .AVIATION...(For the 06Z TAFs through 06Z Tuesday Night) Issued at 1119 PM CDT MON AUG 18 2014 VFR prevails at KTOP/KFOE/KMHK with main concern being TSRA potential. Cluster of TSRA over north central KS is progged to gradually dissipate towards the southeast overnight. Short term guidance maintains scattered TSRA aft 08Z so will leave VCTS mention through 11Z at KMHK and 14Z at KTOP/KFOE. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...63 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS JACKSON KY
1239 AM EDT TUE AUG 19 2014 .UPDATE... ISSUED AT 1130 PM EDT MON AUG 18 2014 UPDATED THE FORECAST TO ISSUE A DENSE FOG ADVISORY FOR EASTERN KENTUCKY. HAD REPORTS OF DENSE FOG MOST OF THE WAY FROM CLAY CITY TO JACKSON. AT SIGNS POINT TO A WIDESPREAD FOG EVENT TONIGHT THAT IS WORSE THAN THE NORMAL AUGUST VALLEY FOG. UPDATE ISSUED AT 702 PM EDT MON AUG 18 2014 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE PRECIPITATION HAS BEEN TAPERING OFF AS THE SHORT WAVE MOVES OFF TO THE EAST. LOWERED THE PROBABILITY OF PRECIPITATION BASED ON CURRENT RADAR AND THE LATEST HRRR OUTPUT. ALSO TOOK OUT THE CHANCE OF THUNDER OUT AS NONE HAS DEVELOPED ALL DAY AND THE MODELS ARE NOT SUPPORTING THEIR DEVELOPMENT IN THE NEAR TERM. THE ONLY THUNDER IS CURRENTLY OVER CENTRAL TENNESSEE. A WEAK FRONT IS STILL QUASI STATIONARY OVER THE AREA. EXPECT TO SEE SOME FAIRLY DENSE FOG TONIGHT...ESPECIALLY IN THE VALLEYS. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 255 PM EDT MON AUG 18 2014 THE LOW PRESSURE SYSTEM THAT BROUGHT THE WIDESPREAD RAIN LAST NIGHT INTO THIS MORNING HAS MOVED INTO WV...TAKING THE DEEPER MOISTURE AND BETTER LIFT WITH IT. A WEST EAST ORIENTED QUASI STATIONARY FRONT REMAINS ACROSS KENTUCKY...AND SCATTERED LIGHT SHOWERS CONTINUE TO MOVE FROM WEST TO EAST ACROSS THE AREA. ANOTHER WAVE OF LOW PRESSURE EVIDENT ON SATELLITE AND RADAR IMAGERY WAS MOVING EAST ALONG THE TN MS BORDER. THIS FEATURE...ALONG WITH THE BOUNDARY ACROSS KY WILL NECESSITATE CONTINUING WITH A CHANCE OF RAIN OVERNIGHT. HOWEVER THE BEST RAIN AND THUNDER CHANCES SHOULD BE SOUTH OF KY TONIGHT. WITH VERY MOIST BOUNDARY LAYER AND SOME BREAKS EXPECTED IN THE CLOUDS THIS EVENING...FOG AND LOW CLOUDS ARE EXPECTED TO DEVELOP DURING THE NIGHT AND LINGER INTO THE MORNING ON TUESDAY. WILL INCLUDE FOG IN THE FORECAST FOR TONIGHT. ON TUESDAY THE NEXT SHORT WAVE IN THIS VERY ACTIVE PATTERN WILL BE PUSHING INTO THE WESTERN GREAT LAKES REGION. AT THE SURFACE A VERY MOIST AND WARM AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KY ON TUESDAY...WHILE A COLD FRONT DROPS SOUTHEAST ACROSS IL AND INDIANA. THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THIS FRONT TUESDAY AFTERNOON. CURRENT THINKING IS THAT SHOWERS AND THUNDERSTORMS THAT DEVELOP TO OUR NORTHWEST ON TUESDAY WILL MOVE INTO OUR AREA TUESDAY NIGHT. WITH THIS THOUGHT IN MIND WILL INTRODUCE LIKELY PROBABILITIES FOR SHOWERS AND THUNDERSTORMS IN THE NORTHERN PART OF OUR FORECAST AREA TUESDAY NIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 255 PM EDT MON AUG 18 2014 MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED. UPPER/MID LEVEL GREAT LAKES LOW WILL MAKE A BEE LINE TO THE MID ATLANTIC COAST BY FRIDAY. MEANWHILE BURGEONING RIDGE TO OUR WEST WILL EXERT ITS INFLUENCE FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER DELTA NORTHWARD INTO THE UPPER MIDWEST. GREAT LAKES LOW WILL PASS TO OUR NORTHEAST DURING ITS MARCH TO THE COAST AND DRAG A SURFACE FRONTAL BOUNDARY ACROSS THE CENTER OF THE OHIO VALLEY REGION. SHARPENING UPPER LEVEL RIDGE AXIS WILL SHIFT SOUTHEASTWARD OVER OUR AREA TOWARDS THE END OF THE EXTENDED AS ENERGY ROUNDS ITS TOP ACROSS THE NORTHERN TIER. DESPITE THE BUILDING RIDGE ALOFT...THE BY THEN QUASI-STATIONARY SFC FRONTAL BOUNDARY WILL REMAIN IN OUR VICINITY AS IT BECOMES ORIENTED PARALLEL TO THE UPPER LEVEL FLOW PATTERN. THUS WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS...THIS BOUNDARY WILL REMAIN CLOSE ENOUGH TO OUR AREA TO SERVE AS A FOCUS FOR ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE LATTER HALF OF THE EXTENDED PERIOD. THE MAINLY DIURNAL SHOWER AND THUNDERSTORM ACTIVITY MAY BE AUGMENTED BY ONE OR TWO ORGANIZED THUNDERSTORM COMPLEXES DROPPING DOWN FROM THE NORTHWEST ON THE EAST SIDE OF THE UPPER RIDGE. FOR SENSIBLE WEATHER...WE WILL SEE THE RETURN OF TRUE SUMMER LIKE WEATHER AS RIDGING TO OUR SOUTHWEST WILL BE STRONG ENOUGH TO SEND TEMPERATURES INTO AND ABOVE SEASONABLE NORMS DESPITE THE INCREASED HUMIDITY. THIS WILL ALSO HELP TO ENHANCE THE DIURNALLY DRIVEN INSTABILITY ACROSS THE AREA RESULTING IN THE BEST CHANCES OF STORMS EACH AFTERNOON AND EVENING. THE THREAT OF RAIN DECREASES BY NEXT WEEKEND AS THE UPPER RIDGE AMPLIFIES AND SHIFTS EASTWARD A BIT...BUT THE POTENTIAL CAN NOT BE TOTALLY REMOVED. IN ADDITION...SHOULD THE RIDGE EXERT A STRONGER INFLUENCE BY SHIFTING JUST A BIT MORE EAST WE MAY BE IN FOR EVEN HOTTER WEATHER BY NEXT WEEKEND. WITH THE 0Z ECMWF ADVERTISING H850 TEMPS UP AROUND 22C TO 24C...THE POSSIBLY EXISTS THAT WE MIGHT SEE SOME OF OUR HOTTEST WEATHER OF THE SUMMER THUS FAR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1239 AM EDT TUE AUG 19 2014 THE MAIN CONCERN FOR THE FIRST 6 HOURS OF THE TAF PERIOD WILL BE LOW CEILINGS AND FOG ACROSS EASTERN KENTUCKY. PARTLY CLOUD SKIES ALONG WITH LIGHT WINDS AND PLENTY OF RAINFALL DURING THE PRIOR DAY HAS LEFT A MOIST AND VERY STABLE BOUNDARY LAYER FOR FOG DEVELOPMENT. A FEW SHOWERS MAY DEVELOP OVERNIGHT BUT WILL BE ISOLATED. HEADING INTO THE DAY...SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE AND KSYM MAY NEED A VCTS MENTION AS THE BEST CHANCE FOR SHOWERS AND STORMS WILL BE IN THE NORTH. OTHERWISE...EXPECT LIGHT WINDS AND DECKS AROUND 5 KFT AFTER THE FOG LIFTS TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ044- 050>052-058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JJ SHORT TERM...SBH LONG TERM...RAY AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
423 AM CDT TUE AUG 19 2014 .DISCUSSION... THE MORNING WATER VAPOR IMAGERY INDICATES THAT THE MAIN SHORTWAVE THAT PRODUCED EXTENSIVE CONVECTION JUST 24 HRS AGO OVER SW AR/EXTREME NRN LA HAS SHIFTED E INTO NRN GA...WITH THE 00Z RAOB 500MB PLOT STILL REVEALING A WEAK SHEAR AXIS THAT EXTENDS FARTHER W ACROSS NRN MS/N LA AND INTO NE TX. MEANWHILE...MOSAIC RADAR IMAGERY ALSO INDICATES A WELL-DEFINED MCV SPINNING E OF SJT...WHICH THE 00Z PROGS HAVE INITILIZED WELL ON AS CONVECTION CONTINUES TO REGENERATE NEAR AND E OF THE CENTER OVER CNTRL TX. THIS CONVECTION HAS PRODUCED A THICK AC CANOPY OVER NE TX/EXTREME NW LA...ALTHOUGH IR IMAGERY DEPICTS WARMING CLOUD TOPS SUGGESTING A WEAKENING TREND IS ONGOING ATTM. THIS MCV CENTER IS PROGGED TO DRIFT NNE ACROSS NCNTRL TX TODAY...WHICH COULD MAINTAIN ELEVATED CONVECTIVE DEBRIS OVER THE NRN HALF OF THE AREA THROUGH AT LEAST THE FIRST HALF OF THE DAY...BEFORE POSSIBLY THINNING THIS AFTERNOON. MY FORECAST MAX TEMPS MAY BE A BIT HIGH TODAY ESPECIALLY IF THIS DEBRIS FIELD HANGS TOUGH TODAY...BUT HAVE PLAYED THE PESSIMIST WITH IT THINNING LATER TODAY...ESPECIALLY AS 09Z TEMPS REMAIN IN THE MID/UPPER 70S. WHILE THE SHORT TERM PROGS DO SUGGEST A WEAK SEABREEZE AFFECTING DEEP E TX/SRN SECTIONS OF NCNTRL LA THIS AFTERNOON...ONLY THE LATEST HRRR RUN DEPICTS AT LEAST ISOLATED CONVECTION DEVELOPING THIS AFTERNOON ALONG THE RESIDUAL SHEAR AXIS...WHICH IS STILL WEAKLY REFLECTED IN THE OTHER SHORT RANGE PROGS. IN ADDITION...THE 09Z SFC ANALYSIS INDICATES A DISTINCT W-E GRADIENT IN SFC THETA-E FROM NEAR OSA TO ALONG THE AR/LA LINE...INDICATIVE OF THE WEAK COLD POOL FROM CONVECTION THAT AFFECTED THESE AREAS MONDAY AFTERNOON/EVENING. GIVEN THESE WEAK SFC AND UPPER AIR FORCING MECHINISMS...AND THE FACT THAT THE CNTRL TX MCV IS PROGGED TO LIFT NNE ACROSS THE STATE TODAY...HAVE EXPANDED SLIGHT CHANCE POPS TO COVER MUCH OF THE REGION THIS AFTERNOON...AND DID CARRY THEM THROUGH THE EVENING BEFORE THEY DIMINISH WITH THE STABILIZING BNDRY LYR. THE SHEAR AXIS IS EXPECTED TO WASH OUT OVERNIGHT WITH THE MCV OPENING UP LATE...AS THE WRN ATLANTIC/CNTRL GULF OF MX UPPER RIDGE EXPECTED TO BRIDGE NWD INTO THE LOWER MS VALLEY WEDNESDAY. STILL SHOULD SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES WEDNESDAY AND THURSDAY AFTERNOONS/EARLY EVENINGS...BEFORE THE UPPER RIDGE CENTER BECOMES ESTABLISHED OVER THE MID-SOUTH/LOWER MS VALLEY FRIDAY. BOTH THE GFS AND ECMWF AMPLIFY THE RIDGE FARTHER N ACROSS THE SRN PLAINS/MS VALLEY FRIDAY...AND KEEPS IT PERSISTENT THROUGH THE WEEKEND INTO EARLY NEXT WEEK. INCREASED SUBSIDENCE WILL RESULT IN MAX TEMPS CLIMBS INTO THE UPPER 90S AREAWIDE...WITH EVEN SOME TRIPLE DIGITS POSSIBLE OVER SOME AREAS THIS WEEKEND/EARLY NEXT WEEK. THE MEDIUM RANGE PROGS DO BEGIN TO SLOWLY NUDGE THE RIDGE E INTO THE SE STATES BY TUESDAY/WEDNESDAY...WITH WEAKNESSES RIDING W BENEATH THE RIDGE ACROSS S LA/SRN MS AS EARLY AS MONDAY. THUS...ISOLATED CONVECTION WILL BE POSSIBLE OVER NCNTRL LA MONDAY AFTERNOON...BEFORE SPREADING FARTHER WNW TO ENCOMPASS MUCH OF THE REGION BY THE END OF THE EXTENDED. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 96 76 97 / 10 10 5 5 5 MLU 95 73 96 74 97 / 20 20 5 5 5 DEQ 94 71 94 71 95 / 20 20 0 0 0 TXK 94 74 96 74 96 / 20 20 0 0 0 ELD 95 72 96 74 97 / 20 20 0 0 0 TYR 94 75 96 76 97 / 10 20 5 5 5 GGG 95 74 96 75 97 / 10 10 5 5 5 LFK 96 75 96 76 97 / 20 20 20 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 AM EDT TUE AUG 19 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 322 PM EDT MON AUG 18 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A FAIRLY STRONG SHRTWV OVER THE NRN PLAINS DRIFTING TO THE ESE INTO NW MN DOWNSTREAM OF A RDG OVER WRN CANADA AND TOWARD A SHRTWV RDG STRETCHING FM HUDSON BAY TOWARD THE SE GREAT LKS ON THE WRN FLANK OF A DEEP TROF OVER THE CNDN MARITIMES. THERE IS ALSO A WEAKER SHRTWV MOVING E THRU THE UPR LKS AHEAD OF THE MAIN DISTURBANCE APRCHG MN...AND THIS FEATURE ALONG WITH ACCOMPANING AXIS OF GREATER H85 THETA E ADVCTN/A FAIRLY MOIST 12Z GRB RAOB /KINX 36C AND PWAT 1.64 INCH OR ALMOST 175 PERCENT OF NORMAL/ HAS BEEN THE FOCUS FOR SOME SCT-NMRS SHOWERS MAINLY OVER CENTRAL CWA TODAY. BUT QUITE A CONTRAST JUST TO THE E WITH THE 12Z APX RAOB DISPLAYING A MUCH DRIER PROFILE...KINX -12C AND PWAT 0.66 INCH OR ONLY 75 PERCENT OF NORMAL. THIS DRIER/STABLE AIRMASS HAS SLOWED THE PROGRESS OF THE SHOWERS INTO THE AREA ARND NEWBERRY SO FAR. THERE ARE MORE NMRS SHOWERS/A FEW TS MOVING INTO WRN LK SUP CLOSER TO THE TRAILING SHRTWV. OTRW...QUITE A BIT OF CLD COVER HAS LIMITED THE DIURNAL RISE OF TEMP AND DESTABILIZATION IN THE ABSENCE OF STEEP LAPSE RATES SHOWN ON EVEN THE MOISTER 12Z GRB RAOB...SO TS HAVE BEEN FEW AND FAR BTWN. BUT SOME HEAVY RAINS HAVE FALLEN UNDER THE STRONGER SHOWERS WITH THE HIER PWAT/DEEPER MSTR. MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS RELATED TO THE TWO DISTURBANCES THAT ARE MOVING THRU MN/THE UPR LKS. LATE TODAY/TNGT...AS TROF OVER QUEBEC SLOWLY EXITS TO THE E...LEAD SHRTWV MOVING THRU THE UPR LKS/ACCOMPANYING AXIS OF H85 THETA E ADVCTN WL DRIFT TO THE E AND BRING SOME SHOWERS TO THE FAR ERN CWA BY 00Z. ALTHOUGH THERE MAY BE ONLY SOME ISOLD/SCT SHOWERS OVER WRN UPR MI WITH SOME H7-5 DRYING MOST OF TODAY...MORE NMRS SHOWERS/SOME TS ASSOCIATED WITH THE STRONGER SHRTWV MOVING INTO MN WL ARRIVE OVER THE FAR W ARND 00Z TOWARD AREA WHERE THE 12Z NAM/REGIONAL CNDN MODEL SHOW HIER MUCAPE UP TO ABOUT 750 J/KG NEAR IWD. BUT SINCE THE MN SHRTWV WL BE TENDING TO DIG ESEWD THRU THE NGT...THE 12Z NAM/ REGIONAL CNDN MODEL INDICATE THE MORE NMRS SHOWERS WL IMPACT WI CLOSER TO MORE VIGOROUS H85-7 MSTR CNVGC/HIER MUCAPE IN THE 500- 1000J/KG THAT WL BE CONFINED TO WI. SO WL MAINTAIN THE HIEST LIKELY POPS TOWARD THE WI BORDER... ALONG WITH THE TS CHANCES PER ABSENCE OF FCST MUCAPE AOA 200 J/KG FARTHER N. BUT DEEP LYR QVECTOR CNVGC/ DEEP SATURATION ON FCST SDNGS ON THE CYC SIDE OF SHRTWV TRACK JUSTIFIES AT LEAST 50-60 POPS OVER THE ENTIRE CWA EVEN IF THE BETTER FORCING/INSTABILITY HOLD TO THE SW. EXPECT LTL DIURNAL TEMP DROP WITH LOTS OF CLDS/LINGERING HIER PWAT IN THE 1.50-1.75 RANGE. ADDED SOME PATCHY FOG...ESPECIALLY IN AREAS OVER THE CENTRAL THAT WL EXPERIENCE UPSLOPE SE FLOW. TUE...EXPECT CONTINUED SCT-NMRS SHOWERS AND A FEW TS AS THE SHRTWV/ SFC LO REFLECTION SLIDE ESEWD THRU NRN WI AND MAINTAINS DEEP MSTR... CYC FLOW AND DEEP LYR QVECTOR CNVGC OVER UPR MI. FCST WL SHOW DIMINISHING POPS IN THE AFTN OVER THE W WITH PASSAGE OF SHRTWV TO THE E AND ARRIVAL OF SOME DNVA/DEEP LYR QVECTOR DVGC AFT 18Z. FOG IN THE MRNG OVER MAINLY THE CENTRAL ZNS WL DSPT SLOWLY WITH DIURNAL HEATING LIMITED BY EXTENSIVE CLD COVER. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 431 PM EDT MON AUG 18 2014 THE 500MB LOW CENTERED OVER UPPER MI AND LAKE SUPERIOR AT 00Z WEDNESDAY WILL SHIFT ACROSS LAKE HURON WEDNESDAY NIGHT/THURSDAY MORNING WITH A BRIEF RIDGE BUILDING ACROSS UPPER MI THURSDAY. THE APEX OF THE RIDGE WILL SHIFT JUST TO OUR E THURSDAY NIGHT. A SIZABLE TROUGH SET UP FROM FROM W AND CENTRAL CANADA THROUGH THE ENTIRE W U.S. WEDNESDAY WILL SLOWLY SHIFT THE N CENTRAL U.S. FOR THE WEEKEND...AND UPPER GREAT LAKES SUNDAY NIGHT/MONDAY. AS FOR THE SFC FEATURES AND WX...THE EXITING SFC LOW OVER N LAKE MI AT 00Z WEDNESDAY WILL LINGER THROUGH THE NIGHT BEFORE SHIFTING TO LOWER MI THROUGH THE DAY WEDNESDAY. WITH WRAP AROUND/UPSLOPE MOISTURE ACROSS THE AREA...EXPECT LIGHT SHOWERS TO LINGER THROUGH MID DAY AT LEAST. THE BEST CHANCE OF THUNDERSTORMS WILL SINK SE WITH THE SFC LOW. IT LOOKS LIKE THE ONLY PERIOD OF MAINLY DRY WEATHER WILL BE LATE WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING...DESPITE THE 500MB RIDGE OVERHEAD THURSDAY THROUGH FRIDAY. THE LARGE HIGH PRESSURE OVER QUEBEC...WITH A RIDGE EXTENDING OVER THE UPPER GREAT LAKES WILL EXIT E ON FRIDAY. THERE STILL LOOKS TO BE PLENTY OF INCONSISTENCIES FOR FRIDAY AFTERNOON ON. WILL CONTINUE TO RUN WITH A GENERAL CONSENSUS FOR THIS PERIOD...WITH HAS AN ELONGATED SFC LOW FROM HUDSON BAY THROUGH MN AND THE CENTRAL PLAINS AT 00Z SUNDAY. THE LOW WILL SLOWLY SHIFT TO ONTARIO/FAR W LAKE SUPERIOR SATURDAY. THIS WOULD BRING WAA TO THE AREA WITH HIGH TEMPS RETURNING TO NEAR NORMAL READINGS FRIDAY AND SATURDAY. THE SFC TROUGH SHOULD BE OVER THE CWA SATURDAY NIGHT/SUNDAY MORNING. HAVE SLOWLY DIMINISHING POPS FOR SUNDAY AND MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 122 AM EDT TUE AUG 19 2014 ALTHOUGH THE SPECIFICS REMAIN UNCERTAIN...LIFR TO VLIFR CONDITIONS SHOULD PREVAIL AT KCMX/KSAW THRU AT LEAST THE MORNING HRS UNDER LIGHT UPSLOPE FLOW/DEEP MOISTURE AND SCT TO AT TIMES NMRS SHRA OVER UPPER MI ASSOCIATED WITH DISTURBANCE MOVING SLOWLY ESEWD FROM MN. AT KIWD...IFR CONDITIONS WILL FALL TO LIFR AND POTENTIALLY VLIFR AS LIGHT UPSLOPE NORTHERLY WIND DEVELOPS LATER IN THE NIGHT. IFR CONDITIONS SHOULD BE THE RULE THIS AFTN AT ALL TERMINALS...THOUGH LOW MVFR CONDITIONS MAY OCCUR AT TIMES. ALL TERMINALS WILL FALL BACK TO LIFR TONIGHT AS ABUNDANT MOISTURE LINGERS ON THE BACKSIDE OF DISTURBANCE MOVING ACROSS THE UPPER LAKES. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 322 PM EDT MON AUG 18 2014 ADDED SOME FOG TO THE FORECAST THRU MUCH OF TUE OVER MAINLY THE CENTRAL LAKE GIVEN ARRIVAL OF DEEPER MOISTURE AND EXPECTED AREA OF LOWER TEMPERATURES NEAR THE LINGERING COOLEST DEEPER WATER. OTHERWISE... EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 AM CDT TUE AUG 19 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON AUG 18 2014 THE MAIN FORECAST ISSUE WILL BE THE POSSIBILITY OF SOME THUNDERSTORM ACTIVITY IN THE FAR SOUTHERN CWA OVERNIGHT. WEST NORTHWEST FLOW ALOFT IS FAIRLY WEAK AND A NEARLY STALLED BOUNDARY ACROSS THE CWA CONTINUES TO DRIFT SOUTH TODAY. LITTLE IF ANY DEVELOPMENT SHOULD DEVELOP ALONG THIS BOUNDARY TODAY INTO THIS EVENING AS A FAIRLY HEALTHY CAP KEEPS THINGS QUIET...DESPITE MODERATE INSTABILITY IN THE 1500 TO 2000 J/KG RANGE FOR CONVECTIVE AVAILABLE POTENTIAL ENERGY. SOME SMALL POP-UPS ARE SHOWING UP JUST NORTH OF THE CWA...BUT THERE SHOULD BE ENOUGH OF A CAP TO TAMP MUCH FURTHER DEVELOPMENT IN THE NORTH. LATER ON TONIGHT...A HEALTHY 40 TO 45 KT JET WILL DEVELOP OVER KANSAS AND WILL CURVE EAST...MOSTLY LIKELY OVER NORTH CENTRAL KANSAS. THIS WILL SET THE STAGE FOR SOME POTENTIAL LOW-LEVEL CONVERGENCE ACROSS OUR SOUTHERN CWA IN NORTH CENTRAL KANSAS AND FAR SOUTHERN NEBRASKA NEAR THE AFOREMENTIONED SURFACE BOUNDARY. THIS COULD BE JUST ENOUGH SUPPORT FOR SOME SMALL HAIL AND GUSTY WIND IN OUR FAR SOUTH AS WELL. THE HRRR IS TRENDING STRONGER WITH SOME DEVELOPMENT OVER THE HIGH PLAINS THIS AFTERNOON...SUPPORTED BY ANOTHER LOW-AMPLITUDE SHORTWAVE TROUGH. THIS COULD BE ENHANCED BY THE DEVELOPING LOW-LEVEL JET IN KANSAS AS THIS POTENTIAL CONVECTION HEADS SOUTH. THE NAM HAS BEEN ADVERTISING SOME ACTIVITY IN THIS VICINITY FOR THE PAST COUPLE OF DAYS. THE PRUDENT ACTION WOULD BE TO PUT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST IN OUR SOUTH. OUR CHANCES OF RAIN ARE LARGELY DEPENDENT ON INITIAL CONVECTION IN THE HIGH PLAINS WITHIN THE STRONGLY UNSTABLE...YET STILL CAPPED ENVIRONMENT TO THE WEST AS THE AFOREMENTIONED TROUGH ENTERS THE CENTRAL PLAINS. THE SREF SOLUTIONS ARE ALSO COMING IN WITH STRONGER SIGNALS TOWARD CONVECTION IN OUR SOUTH AS WELL. FOR TUESDAY...KEEPING IT QUIET WITH THE THINKING THAT THERE SHOULD BE ENOUGH OF A CAP FROM PRECLUDING DEVELOPMENT UNTIL THE EVENING HOURS. HIGH PLAINS CONVECTION COULD DEVELOP DURING THE DAY...BUT SHOULD HOLD OFF MAKING IT HERE UNTIL EVENING...WHEN A LOW-LEVEL JET AXIS DEVELOPS JUST TO THE WEST OF THE CWA. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON AUG 18 2014 GUIDANCE SUGGESTS UPPER TROPOSPHERIC RIDGING WILL EXIST OVER THE CENTRAL CONUS TO START THE LONG TERM FORECAST PERIOD. THE RIDGE AXIS IS EXPECTED TO SHIFT EAST SOMEWHAT BY THURSDAY OR FRIDAY HOWEVER...ALLOWING FOR MORE OF A SOUTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA LATE THIS WEEK INTO EARLY NEXT WEEK. THE AXIS OF A 35-40KT LOWER TROPOSPHERIC JET STREAK...JUST ABOVE THE BOUNDARY LAYER...IS EXPECTED DEVELOP FROM WESTERN KANSAS INTO SOUTH CENTRAL NEBRASKA TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. THERMAL ADVECTION ALONG THIS AXIS APPEARS AS THOUGH IT WILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS NORTHEASTERN PORTIONS OF OUR CWA...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. WENT AHEAD WITH 20-30% POPS ACROSS OUR NORTHEAST TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AS A RESULT. ON OVERALL LACK IN OMEGA SHOULD THEN PROVIDE DRY CONDITIONS TO OUR AREA THROUGH MUCH OF THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON HOWEVER...THE NAM AND OPERATIONAL GFS BOTH SUGGEST CONVECTION WILL INITIATE OVER THE CENTRAL HIGH PLAINS...AND THEN MOVE EAST INTO OUR AREA WEDNESDAY EVENING AND OVERNIGHT. GIVEN THIS...WENT AHEAD WITH 20-30% POPS ACROSS MUCH OF THE CWA WEDNESDAY EVENING AND NIGHT. ALTHOUGH OMEGA IS EXPECTED TO REMAIN WEAK THROUGH THE DAY THURSDAY AS WELL...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST A NEARLY DRY ADIABATIC TEMPERATURE PROFILE WILL BE REALIZED FROM THE SURFACE TO JUST ABOVE 700MB ACROSS MUCH OF THE CWA...THUS ALLOWING CONVECTIVE TEMPERATURE READINGS TO BE REACH AND PROVIDING FOR ISOLATED THUNDERSTORM DEVELOPMENT. THIS IS A SOLUTION ALSO SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. GIVEN ALL THIS...WENT AHEAD WITH ~20% POPS ACROSS MUCH OF THE CWA THURSDAY AFTERNOON AND EVENING. HEADING INTO THURSDAY NIGHT AND BEYOND...GUIDANCE SUGGESTS MULTIPLE UPPER TROPOSPHERIC PERTURBATIONS COULD MOVE OVER THE CENTRAL PLAINS AS THE SOUTHWESTERLY UPPER TROPOSPHERIC FLOW INTENSIFIES. ALLBLEND RESPONDED BY PROVIDING 20-50% POPS TO MANY AREAS ACROSS THE CWA THURSDAY NIGHT THROUGH MONDAY...AND THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART. FORECAST PROXIMITY SOUNDINGS FROM THE NORTHEASTERN CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST STORM-ACCESSIBLE POTENTIAL ENERGY WILL NOT EXCEED 200-300J/KG TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AND THUS...WILL HOLD OFF FROM ANY MENTION OF SEVERE WEATHER TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. CONVECTION ALONG THE CENTRAL HIGH PLAINS WEDNESDAY AFTERNOON AND EVENING WILL LIKELY HAVE THE CAPABILITY TO BE STRONG...BUT THERE IS CONSIDERABLE UNCERTAINTY AS TO HOW LONG THIS CONVECTION WILL BE ABLE TO MAINTAIN ITS INTENSITY AS IT MOVES EAST INTO OUR AREA. GIVEN THIS UNCERTAINTY...WILL HOLD OFF FROM ANY MENTION OF SEVERE WEATHER ACROSS OUR AREA WEDNESDAY EVENING AND LET FUTURE SHIFTS REEVALUATE. BEYOND WEDNESDAY EVENING...AT THIS TIME THERE ARE NO OVERWHELMING SIGNALS OF A SIGNIFICANT SEVERE WEATHER OUTBREAK. ALTHOUGH A FEW HIT AND MISS STRONG TO SEVERE STORMS PROBABLY CANNOT BE RULED OUT...DUE TO THE UNCERTAINTY WILL LEAVE OUT ANY MENTION OF SEVERE WEATHER WEDNESDAY NIGHT AND BEYOND. LITTLE CHANGE IN THE LOWER TROPOSPHERIC AIR MASS SHOULD PROMOTE SIMILAR TEMPERATURE READINGS FROM DAY TO DAY WEDNESDAY THROUGH SATURDAY...WITH AFTERNOON HIGHS IN THE UPPER 80S AND 90S AND OVERNIGHT LOWS IN THE 60S AND LOWER 70S EXPECTED FOR THE MOST PART. BEYOND SATURDAY...GUIDANCE DOES SUGGEST A LOWER TROPOSPHERIC BAROCLINIC ZONE WILL MOVE ACROSS THE AREA...THUS ALLOWING A COOLER LOWER TROPOSPHERIC AIR MASS INTO THE REGION. AFTERNOON HIGHS IN THE UPPER 70S TO MID 80S AND LOWS GENERALLY IN THE 60S ARE CURRENTLY EXPECTED TO FINISH THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1230 AM CDT TUE AUG 19 2014 THUNDERSTORMS ARE WELL SOUTH OF THE TAF SITES EARLY THIS MORNING. MOSTLY CLEAR SKIES ARE EXPECTED THROUGH THE PERIOD. LIGHT WINDS WILL TURN TO THE SOUTHEAST DURING THE DAY AS A SURFACE HIGH MOVES OFF TO THE EAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...BRYANT AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1256 AM CDT TUE AUG 19 2014 .UPDATE... ISSUED AT 1231 AM CDT TUE AUG 19 2014 OUT OF RESPECT FOR THE NAM...WHICH WAS UPGRADED LAST WEEK...AND THE HIRES ARW...ISOLATED TO SCATTERED THUNDERSTORMS WERE EXPANDED ON TUESDAY EVENING/NIGHT. THE MAIN FOCUS TONIGHT WILL BE ON POSSIBLE FOG DEVELOPMENT THIS MORNING ALONG WITH THE POTENTIAL FOR RAINFALL ON ALREADY SATURATED SOILS TUESDAY NIGHT THROUGH THE WEEKEND. UPDATE ISSUED AT 935 PM CDT MON AUG 18 2014 NO SIGNIFICANT UPDATES THIS EVENING. PRECIPITATION HAS ALL BUT ENDED OVER EASTERN NORTH DAKOTA...THUS CLEAR TO PARTLY CLOUDY SKIES EXPECTED TONIGHT WITH PATCHY FOG POSSIBLE AFTER MIDNIGHT. CURRENT FORECAST LOWS IN THE 50S LOOK REASONABLE. UPDATE ISSUED AT 638 PM CDT MON AUG 18 2014 ISOLATED THUNDERSHOWERS CONTINUE TO DISSIPATE ACROSS EASTERN PORTIONS OF CENTRAL NORTH DAKOTA. HAVE REMOVED ALL EVENING POPS EXCEPT FOR JUST A SLIGHT CHANCE FAR EAST THROUGH 9 PM. OTHERWISE MOSTLY CLEAR SKIES TONIGHT WITH LIGHT WINDS. PREVIOUS FORECAST HAD A MENTION OF PATCHY FOG AFTER MIDNIGHT...WHICH LOOKS GOOD. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 DIURNAL CONVECTION THROUGH SUNSET THIS EVENING AND FOG TONIGHT HIGHLIGHT THE SHORT TERM. DIURNAL SCATTERED CONVECTION IS EXPECTED TO REMAIN FOCUSED ACROSS THE SOUTH CENTRAL AND JAMES RIVER VALLEY GIVEN RADAR AND SATELLITE TRENDS THROUGH 1930 UTC...AND THE 16-17 UTC HRRR ITERATIONS. MODEST INSTABILITY AND WEAK SHEAR ARE EXPECTED TO KEEP STORMS BELOW SEVERE LIMITS. HOWEVER...THE NON SUPERCELL TORNADO OR LANDSPOUT PARAMETER HAS A LOCAL MAXIMA ACROSS THE JAMES RIVER VALLEY INTO THE SOUTHERN RED RIVER VALLEY WITH STEEP LOW LEVEL LAPSE RATES AND ENVIRONMENTAL VORTICITY. THUS...WOULD NOT BE SURPRISED BY A FUNNEL CLOUD REPORT. FOR TONIGHT...WITH WEAK SURFACE HIGH PRESSURE IN PLACE...CLEAR SKIES...LIGHT WINDS AND PLENTIFUL MOISTURE FROM WEEKEND RAINS...AREAS OF FOG ARE POSSIBLE ACROSS MUCH OF THE AREA TONIGHT. TUESDAY WILL BE THE ONLY DRY DAY IN THE FORECAST UNDER SHORTWAVE RIDGING BEFORE A RETURN TO AN ACTIVE WEATHER PATTERN THROUGH THE EXTENDED. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM CDT MON AUG 18 2014 A SLOW MOVING TROUGH EXTENDING FROM THE NORTHWEST TERRITORIES WILL PRODUCE CHANCES FOR WIDESPREAD SHOWERS/THUNDERSTORMS FROM WEDNESDAY INTO THE WEEKEND. CHANCES FOR PRECIPITATION WILL CONTINUE THROUGH THE EXTENDED...AS UNSETTLED SOUTHWESTERLY FLOW REMAINS OVER THE AREA. HEAVY RAINFALL IS EXPECTED OVER WESTERN AND CENTRAL PORTIONS OF THE STATE WEDNESDAY INTO THURSDAY...WITH ADDITIONAL RAINFALL THROUGH THE WEEKEND. WESTERN AND CENTRAL AREAS HAVE ALREADY BEEN SATURATED WITH ABUNDANT RAINFALL...FLOODING ISSUES REMAIN A CONCERN. TEMPERATURES WILL NEAR AVERAGE FOR WEDNESDAY AND THURSDAY. A COOLER AIRMASS BEGINS MOVING INTO THE AREA BY FRIDAY MORNING...HIGHS WILL RANGE BETWEEN 10 AND 15 DEGREES BELOW AVERAGE THROUGH THE REST OF THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1231 AM CDT TUE AUG 19 2014 AREAS OF FOG MAY DEVELOP THIS MORNING AND LAST UNTIL 13Z. KJMS HAS THE BEST POTENTIAL FOR IFR BECAUSE OF RAINFALL THERE ON MONDAY...SO VISIBILITY REDUCTIONS HELD TO MVFR AT KDIK/KISN WHERE SOME REDUCTION HAS ALREADY BEEN OBSERVED. THUNDERSTORMS ARE POSSIBLE AFTER 00Z AT KISN/KMOT/KDIK. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SCHECK SHORT TERM...AYD LONG TERM...AC AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
531 AM EDT TUE AUG 19 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF A WEAK FRONT WHICH WILL APPROACH THIS AFTERNOON AND EVENING. THE FRONT WILL STALL ALONG THE OHIO VALLEY WEDNESDAY...THEN GRADUALLY LIFT NORTHEAST THROUGH THE END OF THE WEEK. DISTURBANCES TRACKING ALONG THE FRONT WILL KEEP THE WEATHER UNSETTLED THROUGH AT LEAST FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO INCLUDE A DENSE FOG ADVISORY ACROSS THE SOUTHERN HALF OF THE AREA WHERE THERE ARE QUITE A FEW OBSERVATIONS OF A QUARTER MILE OR LESS. LIGHT FOG WILL EXIST ELSEWHERE. PREVIOUS DISCUSSION... FAIRLY WEAK FLOW PATTERN OVER THE EASTERN CONUS TODAY AS A MID/UPPER LEVEL TROUGH DIGS INTO THE WESTERN GREAT LAKES. A WEAK SURFACE BOUNDARY ALONG THE OHIO RIVER WILL LIFT NORTH IN RESPONSE TO LOW PRESSURE ATTENDANT TO THE MID AND UPPER LEVEL FEATURE. A FEW RUNS OF THE RAP AND HRRR TRIED TO DEVELOP A FEW SHOWERS WITH THE BOUNDARY THIS MORNING...BUT HAVE KEPT THE FORECAST DRY BASED ON LATEST OBSERVATIONS. AS DAYTIME HEATING BUILDS...SOME CONVECTION MAY START DEVELOPING AROUND THE MIDDAY HOURS...BUT THIS WILL BE ISOLATED AT BEST. THE MAIN FOCUS WILL BE TO OUR WEST...AS SHOWERS AND STORMS FIRE ALONG A PREFRONTAL TROUGH. EXACT TIMING IS STILL IN QUESTION...BUT SOME STORMS COULD ARRIVE IN WEST CENTRAL OHIO BY LATE AFTERNOON. WILL DISCUSS THESE STORMS FURTHER IN THE SHORT TERM SECTION. BASED ON THE TEMPERATURE TRENDS FROM MONDAY...WE COULD WARM PRETTY NICELY WITH A LACK OF PRECIPITATION DURING PEAK HEATING. WENT A LITTLE ABOVE GUIDANCE FOR MOST... IN THE MID TO UPPER 80S AND INCREASING DEW POINTS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AN AREA OF SCATTERED TO NUMEROUS STORMS WILL BE CROSSING THE AREA DURING THE EVENING HOURS. MODERATE INSTABILITY...LIKELY BETWEEN 1-2K J/KG...WILL HAVE DEVELOPED DURING THE AFTERNOON. RICHER LOW LEVEL MOISTURE LOOKS LIKE IT WILL STAY TO THE SOUTHWEST OF OUR AREA. WHILE THERE IS SOME INCREASED MID LEVEL FLOW ASSOCIATED WITH THE DIGGING TROUGH...THE HIGHEST BULK SHEAR VALUES ARE GENERALLY TO OUR SOUTHWEST AS WELL. WITH THAT SAID...THERE ARE ENOUGH INGREDIENTS IN PLACE FOR AT LEAST SOME STRONGER STORMS...ESPECIALLY WEST OF I-75 WHERE SPC HAS HOISTED A SLIGHT RISK. A WEAKENING TREND IS EXPECTED THROUGH THE EVENING AS INSTABILITY IS LOST...BUT THE TIMING WILL BE IMPORTANT TO WHEN THIS OCCURS. INTERESTINGLY...THE LATEST MODEL RUNS ARE FOCUSING THE GREATEST COVERAGE NORTH OF THE OHIO RIVER...LIKELY CLOSEST TO THE STRONGER FORCING...SO ADJUSTED THE POPS ACCORDINGLY. THE NAM SEEMS A LITTLE TOO BULLISH IN DEVELOPING ADDITIONAL CONVECTION ALONG THE WEAK SURFACE FRONT. BASED ON DEEP LAYER MOISTURE...EXPECT A DRYING TREND TOWARD WEDNESDAY MORNING. MUGGY LOWS IN THE UPPER 60S TO AROUND 70. FORCING ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE PUSHING EAST ON WEDNESDAY...BUT THERE ARE SOME INDICATIONS THE SURFACE FRONT COULD REACTIVATE IN CENTRAL OHIO AROUND MIDDAY BEFORE PUSHING EAST. THE TAIL END OF THE FRONT WILL STALL ACROSS NORTHERN KENTUCKY...WARRANTING CHANCE POPS THERE AS WELL. HIGH TEMPERATURES IN THE MID 80S. FROM WEDNESDAY NIGHT THROUGH FRIDAY...MID AND UPPER LEVEL RIDGING WILL BEGIN BUILDING ACROSS THE CENTER OF THE COUNTRY AS TROUGHING DIGS INTO THE PACIFIC NORTHWEST. THIS WILL PLACE THE OHIO VALLEY UNDER INCREASING NORTHWEST FLOW WITH POTENTIAL FOR SOUTHEASTWARD DIVING DISTURBANCES. A NW-SE LOW LEVEL BAROCLINIC ZONE WILL TIGHTEN AS WELL WITH MOISTURE POOLED ALONG IT. THE CHANCE OF STORMS WILL INCREASE WEDNESDAY NIGHT IN THE TRI STATE AREA...OVERSPREADING THE REST OF THE REGION ON THURSDAY. FRIDAY WILL REMAIN UNSETTLED AS THE CORRIDOR OF FORCING MOVES ONLY SLIGHTLY NORTHEAST IN RESPONSE TO THE BUILDING RIDGE. EXPECT INCREASINGLY MUGGY CONDITIONS WITH HIGHS GENERALLY IN THE MID TO UPPER 80S AND LOWS ON EITHER SIDE OF 70. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... MID/UPPER LEVEL RIDGING OVER THE CENTRAL UNITED STATES WILL SHIFT SLOWLY EAST TOWARD THE LOWER OHIO VALLEY THROUGH THE WEEKEND. PCPN CHANCES SHOULD THEN BECOME MORE SUPPRESSED AS WE PROGRESS THROUGH THE WEEKEND AS THE RIDGE BUILDS IN FROM THE SOUTHWEST. SHORT WAVE ENERGY MOVING ACROSS THE GREAT LAKES WILL BEGIN TO WEAKEN THE RIDGE FROM THE NORTH LATE IN THE PERIOD...EVENTUALLY HELPING TO PUSH A COLD FRONT DOWN TOWARD OUR AREA. THIS MAY ALLOW FOR A CHANCE OF PCPN TOWARD THE END OF THE PERIOD ON MONDAY...BUT GIVEN THE MODEL DIFFERENCES WITH THE TIMING...WILL MAINTAIN A DRY FORECAST AT THIS POINT. TEMPERATURES WILL BE SOMEWHAT DEPENDENT ON THE TIMING AND DEGREE OF THUNDERSTORM ACTIVITY THROUGH LATE IN THE WEEK. HOWEVER...WITH THE HIGH BUILDING IN FROM THE SOUTHWEST...GENERALLY EXPECT A GRADUAL WARMING TREND TO ABOVE NORMAL HIGH TEMPERATURES THROUGH THE WEEKEND. OVERNIGHT LOWS WILL REMAIN ON THE WARM SIDE TOO WITH LOWS MOSTLY IN THE UPPER 60S TO AROUND 70 DEGREES. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... FIRST OF ALL...PARTLY CLOUDY TO MOSTLY CLEAR SKIES OVERNIGHT ALONG WITH AMPLE LOW LEVEL MOISTURE AND LIGHT TO CALM WINDS WILL RESULT IN PATCHY TO AREAS OF FOG AT THE TERMINALS. THE WORST CONDITIONS ARE EXPECTED AT THE SOUTHERN TERMINALS WHERE MOISTURE IS THE HIGHEST. HAVE IFR CONDITIONS AT KILN...KCVG AND KLUK...WITH SOME LIFR/VLIFR POSSIBLE AT KILN AND AND KLUK. FOG SHOULD BURN OFF BY 14Z. A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE WESTERN GREAT LAKES TODAY AND TONIGHT. FORECAST MODELS INDICATE THAT A PREFRONTAL TROF AXIS WILL TRAIL SOUTH FROM THIS LOW AND WILL PUSH EAST INTO OUR REGION LATE THIS AFTERNOON INTO THE EARLY MORNING HOURS OF WEDNESDAY. THIS TROF AXIS WILL THEN BE FOLLOWED BY A WEAK COLD FRONT LATE TONIGHT INTO WEDNESDAY MORNING. FOR LATER TODAY AND TONIGHT...DAYTIME INSTABILITY AND ENOUGH SHEAR/CONVERGENCE WITH THE PREFRONTAL TROF AXIS SHOULD BRING AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS TO THE TERMINALS THIS EVENING INTO THE EARLY MORNING HOURS OF WEDNESDAY. HAVE PLACED VCTS/CB DESCRIPTORS AT THE SITES WHEN THIS IS MOST LIKELY TO OCCUR...BETWEEN 00Z AND 06Z. THE WEAK COLD FRONT WILL FOLLOW BEHIND THE TROF LATE TONIGHT...BUT IT APPEARS CONVERGENCE WILL BE WEAKER AND INSTABILITY WILL HAVE WANED SOME...SO COVERAGE APPEARS LESS WITH THIS BOUNDARY. OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR OHZ070>073- 077>082-088. KY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ089>100. IN...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
448 AM EDT TUE AUG 19 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF A WEAK FRONT WHICH WILL APPROACH THIS AFTERNOON AND EVENING. THE FRONT WILL STALL ALONG THE OHIO VALLEY WEDNESDAY...THEN GRADUALLY LIFT NORTHEAST THROUGH THE END OF THE WEEK. DISTURBANCES TRACKING ALONG THE FRONT WILL KEEP THE WEATHER UNSETTLED THROUGH AT LEAST FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FAIRLY WEAK FLOW PATTERN OVER THE EASTERN CONUS TODAY AS A MID/UPPER LEVEL TROUGH DIGS INTO THE WESTERN GREAT LAKES. A WEAK SURFACE BOUNDARY ALONG THE OHIO RIVER WILL LIFT NORTH IN RESPONSE TO LOW PRESSURE ATTENDANT TO THE MID AND UPPER LEVEL FEATURE. A FEW RUNS OF THE RAP AND HRRR TRIED TO DEVELOP A FEW SHOWERS WITH THE BOUNDARY THIS MORNING...BUT HAVE KEPT THE FORECAST DRY BASED ON LATEST OBSERVATIONS. AS DAYTIME HEATING BUILDS...SOME CONVECTION MAY START DEVELOPING AROUND THE MIDDAY HOURS...BUT THIS WILL BE ISOLATED AT BEST. THE MAIN FOCUS WILL BE TO OUR WEST...AS SHOWERS AND STORMS FIRE ALONG A PREFRONTAL TROUGH. EXACT TIMING IS STILL IN QUESTION...BUT SOME STORMS COULD ARRIVE IN WEST CENTRAL OHIO BY LATE AFTERNOON. WILL DISCUSS THESE STORMS FURTHER IN THE SHORT TERM SECTION. BASED ON THE TEMPERATURE TRENDS FROM MONDAY...WE COULD WARM PRETTY NICELY WITH A LACK OF PRECIPITATION DURING PEAK HEATING. WENT A LITTLE ABOVE GUIDANCE FOR MOST... IN THE MID TO UPPER 80S AND INCREASING DEW POINTS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AN AREA OF SCATTERED TO NUMEROUS STORMS WILL BE CROSSING THE AREA DURING THE EVENING HOURS. MODERATE INSTABILITY...LIKELY BETWEEN 1-2K J/KG...WILL HAVE DEVELOPED DURING THE AFTERNOON. RICHER LOW LEVEL MOISTURE LOOKS LIKE IT WILL STAY TO THE SOUTHWEST OF OUR AREA. WHILE THERE IS SOME INCREASED MID LEVEL FLOW ASSOCIATED WITH THE DIGGING TROUGH...THE HIGHEST BULK SHEAR VALUES ARE GENERALLY TO OUR SOUTHWEST AS WELL. WITH THAT SAID...THERE ARE ENOUGH INGREDIENTS IN PLACE FOR AT LEAST SOME STRONGER STORMS...ESPECIALLY WEST OF I-75 WHERE SPC HAS HOISTED A SLIGHT RISK. A WEAKENING TREND IS EXPECTED THROUGH THE EVENING AS INSTABILITY IS LOST...BUT THE TIMING WILL BE IMPORTANT TO WHEN THIS OCCURS. INTERESTINGLY...THE LATEST MODEL RUNS ARE FOCUSING THE GREATEST COVERAGE NORTH OF THE OHIO RIVER...LIKELY CLOSEST TO THE STRONGER FORCING...SO ADJUSTED THE POPS ACCORDINGLY. THE NAM SEEMS A LITTLE TOO BULLISH IN DEVELOPING ADDITIONAL CONVECTION ALONG THE WEAK SURFACE FRONT. BASED ON DEEP LAYER MOISTURE...EXPECT A DRYING TREND TOWARD WEDNESDAY MORNING. MUGGY LOWS IN THE UPPER 60S TO AROUND 70. FORCING ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE PUSHING EAST ON WEDNESDAY...BUT THERE ARE SOME INDICATIONS THE SURFACE FRONT COULD REACTIVATE IN CENTRAL OHIO AROUND MIDDAY BEFORE PUSHING EAST. THE TAIL END OF THE FRONT WILL STALL ACROSS NORTHERN KENTUCKY...WARRANTING CHANCE POPS THERE AS WELL. HIGH TEMPERATURES IN THE MID 80S. FROM WEDNESDAY NIGHT THROUGH FRIDAY...MID AND UPPER LEVEL RIDGING WILL BEGIN BUILDING ACROSS THE CENTER OF THE COUNTRY AS TROUGHING DIGS INTO THE PACIFIC NORTHWEST. THIS WILL PLACE THE OHIO VALLEY UNDER INCREASING NORTHWEST FLOW WITH POTENTIAL FOR SOUTHEASTWARD DIVING DISTURBANCES. A NW-SE LOW LEVEL BAROCLINIC ZONE WILL TIGHTEN AS WELL WITH MOISTURE POOLED ALONG IT. THE CHANCE OF STORMS WILL INCREASE WEDNESDAY NIGHT IN THE TRI STATE AREA...OVERSPREADING THE REST OF THE REGION ON THURSDAY. FRIDAY WILL REMAIN UNSETTLED AS THE CORRIDOR OF FORCING MOVES ONLY SLIGHTLY NORTHEAST IN RESPONSE TO THE BUILDING RIDGE. EXPECT INCREASINGLY MUGGY CONDITIONS WITH HIGHS GENERALLY IN THE MID TO UPPER 80S AND LOWS ON EITHER SIDE OF 70. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... MID/UPPER LEVEL RIDGING OVER THE CENTRAL UNITED STATES WILL SHIFT SLOWLY EAST TOWARD THE LOWER OHIO VALLEY THROUGH THE WEEKEND. PCPN CHANCES SHOULD THEN BECOME MORE SUPPRESSED AS WE PROGRESS THROUGH THE WEEKEND AS THE RIDGE BUILDS IN FROM THE SOUTHWEST. SHORT WAVE ENERGY MOVING ACROSS THE GREAT LAKES WILL BEGIN TO WEAKEN THE RIDGE FROM THE NORTH LATE IN THE PERIOD...EVENTUALLY HELPING TO PUSH A COLD FRONT DOWN TOWARD OUR AREA. THIS MAY ALLOW FOR A CHANCE OF PCPN TOWARD THE END OF THE PERIOD ON MONDAY...BUT GIVEN THE MODEL DIFFERENCES WITH THE TIMING...WILL MAINTAIN A DRY FORECAST AT THIS POINT. TEMPERATURES WILL BE SOMEWHAT DEPENDENT ON THE TIMING AND DEGREE OF THUNDERSTORM ACTIVITY THROUGH LATE IN THE WEEK. HOWEVER...WITH THE HIGH BUILDING IN FROM THE SOUTHWEST...GENERALLY EXPECT A GRADUAL WARMING TREND TO ABOVE NORMAL HIGH TEMPERATURES THROUGH THE WEEKEND. OVERNIGHT LOWS WILL REMAIN ON THE WARM SIDE TOO WITH LOWS MOSTLY IN THE UPPER 60S TO AROUND 70 DEGREES. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... FIRST OF ALL...PARTLY CLOUDY TO MOSTLY CLEAR SKIES OVERNIGHT ALONG WITH AMPLE LOW LEVEL MOISTURE AND LIGHT TO CALM WINDS WILL RESULT IN PATCHY TO AREAS OF FOG AT THE TERMINALS. THE WORST CONDITIONS ARE EXPECTED AT THE SOUTHERN TERMINALS WHERE MOISTURE IS THE HIGHEST. HAVE IFR CONDITIONS AT KILN...KCVG AND KLUK...WITH SOME LIFR/VLIFR POSSIBLE AT KILN AND AND KLUK. FOG SHOULD BURN OFF BY 14Z. A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE WESTERN GREAT LAKES TODAY AND TONIGHT. FORECAST MODELS INDICATE THAT A PREFRONTAL TROF AXIS WILL TRAIL SOUTH FROM THIS LOW AND WILL PUSH EAST INTO OUR REGION LATE THIS AFTERNOON INTO THE EARLY MORNING HOURS OF WEDNESDAY. THIS TROF AXIS WILL THEN BE FOLLOWED BY A WEAK COLD FRONT LATE TONIGHT INTO WEDNESDAY MORNING. FOR LATER TODAY AND TONIGHT...DAYTIME INSTABILITY AND ENOUGH SHEAR/CONVERGENCE WITH THE PREFRONTAL TROF AXIS SHOULD BRING AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS TO THE TERMINALS THIS EVENING INTO THE EARLY MORNING HOURS OF WEDNESDAY. HAVE PLACED VCTS/CB DESCRIPTORS AT THE SITES WHEN THIS IS MOST LIKELY TO OCCUR...BETWEEN 00Z AND 06Z. THE WEAK COLD FRONT WILL FOLLOW BEHIND THE TROF LATE TONIGHT...BUT IT APPEARS CONVERGENCE WILL BE WEAKER AND INSTABILITY WILL HAVE WANED SOME...SO COVERAGE APPEARS LESS WITH THIS BOUNDARY. OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
152 AM EDT TUE AUG 19 2014 .SYNOPSIS... LOW PRESSURE OVER SOUTHERN OHIO WILL MOVE EAST TO THE VIRGINIA COAST BY TUESDAY MORNING. A STATIONARY FRONT ACROSS CENTRAL OHIO WILL BE DRAWN SOUTH IN THE WAKE OF THE LOW. ANOTHER LOW WILL MOVE INTO THE WESTERN GREAT LAKES OVERNIGHT AND EXPAND ACROSS THE CENTRAL LAKES TUESDAY BRINGING THE FRONT BACK NORTH INTO THE AREA AS A WARM FRONT. THE LOW WILL REMAIN IN THE AREA THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... OVERNIGHT WE ARE EXPECTING DRY CONDITIONS. NOT SURE WHY HRRR KEEPS ON AND OFF LIGHT SHRA/SPRINKLES OVER THE EAST THRU THE NIGHT. THIS AREA IS WHERE THE MODELS HAVE THE DRIEST AIR SO IT DOES NOT SEEM TO MAKE SENSE...UNLESS ITS TRYING TO INDICATE MID LEVEL ATTEMPTS AT PRECIP/VIRGA. MORE CLOUDS ON THE WAY FROM THE WEST OVERNIGHT ASSOCIATED WITH THE LOW MOVING INTO THE WESTERN LAKES. EXPECTING THOSE AFTER MIDNIGHT IN THE WEST ALONG WITH A SLIGHT CHANCE OF SHOWERS OR A THUNDERSTORM TOWARD DAYBREAK. LOWS SHOULD BE IN THE LOWER 60S WITH A FEW UPPER 50S EAST. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... THE SOUTHERN OHIO LOW WILL HAVE REACHED THE VIRGINIA COAST BY MORNING WITH THE NEXT LOW MOVING INTO/ THROUGH THE WESTERN LAKES. THIS LOW WILL DOMINATE THE SHORT TERM PERIOD AS IT ROTATES THROUGH THE GREAT LAKES REGION THROUGH MID WEEK. ALSO THE FRONT TO OUR SOUTH WILL BEGIN MOVING NORTHEAST AS A WARM FRONT AS THE LOW APPROACHES AND BY MORNING IT SHOULD EXTEND FROM NEAR CHICAGO TO CINCINNATI. FOLLOWED THE SREF FOR PRECIP TIMING TUESDAY WHICH BRINGS CHANCE POPS INTO THE WEST DURING THE MORNING...INCREASING TO LIKELY BY MID DAY AS THE REST OF THE AREA INCREASES TO CHANCE POPS. BY EARLY EVENING SPREAD THE LIKELY POPS FURTHER EAST ACROSS THE CENTRAL COUNTIES...EVENTUALLY EXPANDING ACROSS THE REMAINDER OF THE EAST LATE EVENING TO OVERNIGHT. WEDNESDAY MORNING THE UPPER LOW WILL REMAIN STUCK OVER NRN MI WITH CONTINUED DIVERGENCE ACROSS NRN OHIO/NWRN PA. AXIS OF DEEPEST MOISTURE WILL BE NEGATIVELY TILTED FROM THE WESTERN LAKES TO PA AND NY. WILL KEEP HIGHEST POPS ACROSS NERN OHIO AND NWRN PA WITH DECREASING CHANCES WEST. THE LOW WILL WEAKEN AND MOVE TO PA/NY THURSDAY AS AN UPPER RIDGE AXIS BUILDS INTO THE UPPER MIDWEST. STILL WILL LIKELY SEE SHOWERS AND THUNDERSTORMS DURING THE DAY GIVEN THE CONTINUED MOISTURE AND DAYTIME HEATING SO WILL CONTINUE WITH CHANCE POPS. TEMPS NEAR NORMAL. && .LONG TERM /FRIDAY THROUGH MONDAY/... UPPER LEVEL LOW MOVES OFF THE EAST COAST ON FRIDAY WITH THE UPPER LEVEL RIDGE OVER THE MISSISSIPPI VALLEY SLOWLY EXPANDING EASTWARD OVER THE WEEKEND. FRIDAY LOOKS LIKE A TRANSITION DAY AND COULD BE ACTIVE WITH SHOWERS AND THUNDERSTORMS AS ENERGY RIDES AROUND THE BUILDING RIDGE. BOTH THE ECMWF AND GFS TRY TO BUILD A STRONG RIDGE OVER THE GREAT LAKES THIS WEEKEND AND EXTENDING NORTHEAST INTO QUEBEC. THIS SHOULD LEAD TO DECREASING CHANCES OF SHOWERS AND THUNDERSTORMS BOTH SATURDAY AND SUNDAY AS MID LEVELS WARM AND WARM FRONT SHIFTS NORTH OF THE AREA. MODELS DO INDICATE SOME LINGERING MOISTURE AND SOMEWHAT OF A BOUNDARY IN PLACE THOUGH SO WILL HOLD ONTO LOW CHANCES OF SHOWERS AND THUNDERSTORMS IN ALL BUT THE EAST WHERE A DRIER EASTERLY FLOW ON THE PERIPHERY OF HIGH PRESSURE TO THE EAST SHOULD LIKELY MAINTAIN DRY CONDITIONS. STILL EXPECT A WARMING TREND OVER THE WEEKEND BUT HAVE BACKED OFF A FEW DEGREES FOR NOW WITH UNCERTAINTY IN CLOUD COVER. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... FORECAST THIS MORNING ALL HINGES ON TIMING OF THE THUNDERSTORM COMPLEX THAT IS CURRENTLY OVER WISCONSIN. POTENTIAL EXISTS THAT THE BULK OF THE THUNDERSTORM ACTIVITY WILL SCOOT EAST ACROSS MICHIGAN INTO ONTARIO. SOME INSTABILITY WILL DEVELOP ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA AND THIS COULD HELP SOME OF THE THUNDERSTORM ACTIVITY TO DEVELOP FURTHER SOUTH. WILL CONTINUE WITH CURRENT FORECAST OF TIMING PRECIPITATION INTO THE FORECAST AREA DURING THE AFTERNOON AND EVENING FROM THE COMPLEX. WILL ALSO KEEP A MENTION OF SHOWERS AND THUNDERSTORMS FOR TONIGHT AS WARM FRONTAL BOUNDARY AND ASSOCIATED MOISTURE MOVE EAST INTO THE REGION. OUTLOOK...NON VFR POSSIBLE IN SHOWERS/THUNDERSTORMS THROUGH FRIDAY. && .MARINE... LAKE ERIE IS LOCATED BETWEEN HIGH PRESSURE TO THE NORTH AND A WEAK AREA OF LOW PRESSURE OVER THE OHIO VALLEY. NORTHEAST TO EAST WINDS HAVE INCREASED TO AROUND 15 KNOTS OR SO ALONG MUCH OF THE SOUTH SHORE OF THE LAKE...WITH WAVES OF 1 TO 3 FEET. THE HIGH WILL BUILD TO THE EAST OVERNIGHT AND WINDS WILL DECREASE AS THE GRADIENT RELAXES...SHIFTING TO EASTERLY AND THEN SOUTHEAST LATE. AN AREA OF LOW PRESSURE WILL MOVE INTO THE WESTERN GREAT LAKES ON TUESDAY THEN MOVE ACROSS LAKE ERIE ON WEDNESDAY BRINGING UNSETTLED WEATHER. WINDS WILL GENERALLY REMAIN 15 KNOTS OR LESS AS THEY SHIFT AROUND TO THE WEST BEHIND THIS SYSTEM. HIGH PRESSURE WILL RETURN ON THURSDAY FOLLOWED BY A SLOW MOVING WARM FRONT THAT WILL LIFT NORTH ACROSS THE LAKE OVER THE WEEKEND. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...ADAMS/TK SHORT TERM...TK LONG TERM...KEC AVIATION...LOMBARDY MARINE...KEC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1111 PM MDT MON AUG 18 2014 .UPDATE... ISSUED AT 806 PM MDT MON AUG 18 2014 00Z KUNR SOUNDING SHOWED A BIT OF MUCAPE. COUPLE OF WEAK SHORTWAVES OVER SOUTH CENTRAL MT/NORTHWEST WY WILL MOVE EAST THROUGH THE SOUTHWEST THIRD OF THE CWA OVERNIGHT BRINGING WITH IT ISOLATED TSRA. LATEST HRRR SEEMS TO PICK UP ON THIS AS WELL AS CURRENT RADAR TRENDS TO OUR WEST. WILL SPREAD POPS FROM CURRENT RADAR RETURNS THROUGH SOUTHWEST THIRD OF CWA TO ACCOUNT WITH UPDATE. && .SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT ISSUED AT 300 PM MDT MON AUG 18 2014 CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHERN MN WITH HIGH PRESSURE OVER CENTRAL MT. UPPER LEVEL ANALYSIS SHOWS TROF OVER SOUTH CENTRAL CANADA...WITH NORTHWESTERLY FLOW OVER MOST OF THE NORTHERN HIGH PLAINS. DRIER AIR IS IN PLACE ACROSS THE AREA FOR TODAY...WITH DEWPOINTS MOSTLY IN THE UPPER 40S AND 50S. SHOWERS AND STORMS THIS AFTERNOON HAVE STAYED TO THE NORTH AND SOUTH OF THE CWA...WITH A FEW STRONG STORMS OVER THE NEB PANHANDLE RIGHT NOW. TEMPS ARE IN THE UPPER 79S TO UPPER 80S WITH BRISK NORTHWESTERLY WINDS ACROSS MUCH OF THE PLAINS. THESE WINDS WILL BEGIN TO DIMINISH BY EARLY EVENING. UNSETTLED WEATHER WILL RETURN LATER ON TUESDAY AND PERSIST AT TIMES THROUGH THE END OF THE WEEK AS HIGH PRESSURE ALOFT MOVES INTO THE SOUTHEASTERN CONUS AND A BROAD TROF DEVELOPS OVER THE WESTERN STATES. DAILY CHANCES FOR SHOWERS AND STORMS CAN BE EXPECTED... ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. FOR TONIGHT...SKIES WILL BE CLEAR TO PARTLY CLOUDY. A WEAK DISTURBANCE IN NORTHWEST FLOW COULD PRODUCE A FEW SHOWERS AND POSSIBLY A STORM LATE TONIGHT INTO EARLY TUESDAY OVER THE BLACK HILLS AREA. WINDS WILL BECOME LIGHT THIS EVENING AND THEN SWITCH TO THE SOUTHEAST OVERNIGHT INTO TUESDAY MORNING AS HIGH PRESSURE PASSES OVER AND EVENTUALLY EAST OF THE AREA. WARMER AIR WILL RETURN ON TUESDAY AS SOUTH-SOUTHEAST WINDS INCREASE. HIGHS WILL BE IN THE MID 80S TO AROUND 90 DEGREES ACROSS THE PLAINS...MOSTLY 80S OVER THE BLACK HILLS. A MORE WIDESPREAD CHANCE FOR STORMS WILL RETURN LATE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS FLOW ALOFT TURNS SOUTHWESTERLY OVER THE HIGH PLAINS. THE SOUTH-SOUTHEAST WINDS WILL ALSO BRING LOW LEVEL MOISTURE BACK INTO THE AREA...WITH INCREASING INSTABILITY INTO TUESDAY NIGHT. WILL GENERALLY KEEP POPS AS IS LATE TUESDAY INTO TUESDAY NIGHT. THE THREAT FOR SEVERE STORMS STILL LOOKS RELATIVELY LOW. HOWEVER...WITH SUFFICIENT INSTABILITY AROUND...ISOLATED STRONG TO MARGINALLY SEVERE STORMS WITH HAIL AND GUSTY WINDS ARE CERTAINLY POSSIBLE LATE IN THE AFTERNOON INTO THE EVENING. && .LONG TERM...WEDNESDAY THROUGH MONDAY ISSUED AT 300 PM MDT MON AUG 18 2014 MEAN WESTERN NOAM TROUGHING WILL PERSIST IN THE PERIOD...WITH MASSIVE EASTERN NOAM RIDGING ENSUING TOWARD THE END OF THE WEEK. THIS WILL SUPPORT A LOCAL PATTERN CHANGE AS LOWER HEIGHTS AND MUCH COOLER TEMPS SPREAD OVER THE NORTHERN PLAINS BY THIS WEEKEND...PER THE WESTERN CONUS TROUGH PHASING WITH A LONG WAVE NORTHERN STREAM TROUGH. ACTIVE SW FLOW CAN BE EXPECTED TO SUPPORT NEAR DAILY CHANCES FOR PRECIP THROUGH THE PERIOD...WITH THE WESTERN CONUS TROUGH SHIFTING EAST OVER THE NORTHERN PLAINS BY LATE THIS WEEKEND. HAVE RETAINED DAILY CHANCES FOR SHRA/TS WITH A WAVERING FRONTAL ZONE OVER THE REGION THROUGH THUR. COLD FRONT WILL SHIFT SE TROUGH THE REGION FRIDAY...WITH CAA SPREADING ACROSS THE REGION VIA GUSTY NW WINDS. CYCLONIC DISTURBED SW FLOW WILL PERSIST THROUGH THE WEEKEND. HOWEVER...GIVEN SIGNALS FOR THE BEST LSA BEING NW OF THE FA...WITH MORE DIURNALLY DRIVEN CHANCES FOR CONVECTION...HAVE BIASED POPS MORE TOWARD CLIMO NUMBERS THIS WEEKEND..ESP GIVEN CONVECTIVE NATURE TO PRECIP. AS FOR TEMPS...SEASONAL NUMBERS WILL PERSIST THROUGH THURS...WITH COOLING CONDITIONS FRI-SUN. TEMPERATURES ARE PROGGED TO BE 5 TO 15 DEGREES BELOW SEASONAL NORMS BY SUNDAY AND MONDAY...ESP HIGH TEMPERATURES. HAVE CONTINUED TO ADD A NEGATIVE BIAS PER HIGHS SAT-MONDAY...WITH MANY PLACES LIKELY STRUGGLING TO REACH 70 ACROSS THE NORTHERN HALF SUNDAY AND MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1109 PM MDT MON AUG 18 2014 MAINLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. A WARM FRONT WILL SHIFT NORTH TONIGHT AND POSSIBLY SUPPORT ISOLATED TSRA. ADDITIONAL TSRA WILL DEVELOP LATER TUESDAY AFTERNOON INTO TUESDAY NIGHT WITH LOCAL MVFR CIGS/VSBYS IN THE STRONGEST STORMS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...HELGESON SHORT TERM...26 LONG TERM...JC AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1131 PM CDT MON AUG 18 2014 .DISCUSSION... UPDATED FOR 06Z AVIATION DISCUSSION && .PREV DISCUSSION... /ISSUED 921 PM CDT MON AUG 18 2014/ UPDATE... A CLUSTER OF SHOWERS AND THUNDERSTORMS ARE SKIRTING PHILLIPS COUNTY ARKANSAS AND COAHOMA COUNTY MISSISSIPPI AT THIS TIME. LATEST HRRR SHOWS THAT THE AREA FROM COAHOMA COUNTY TO MONROE COUNTY MISSISSIPPI COULD CONTINUE SEE THIS ACTIVITY INTO THE OVERNIGHT HOURS. OTHERWISE...EXPECT MAINLY DRY CONDITIONS. WILL ADJUST POPS OTHERWISE REST OF THE FORECAST LOOKS GOOD. KRM DISCUSSION... /ISSUED 253 PM CDT MON AUG 18 2014/ SKIES ARE PARTLY CLOUDY OVER MUCH OF THE FORECAST AREA THIS AFTERNOON WITH TEMPERATURES RANGING FROM THE LOWER 70S TO MID 80S. SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO MOVE ACROSS PORTIONS OF THE FORECAST AREA. EARLIER THIS AFTERNOON WE HAD SOME HEAVY RAINFALL OVER PORTIONS OF WEST TENNESSEE WITH 3 TO 5 INCHES OF RAIN FALLING IN A FEW LOCATIONS. THE UPPER LEVEL DISTURBANCE WHICH HELPED PRODUCE ALL THE THUNDERSTORM ACTIVITY WAS MOVING ACROSS NORTH MISSISSIPPI THIS AFTERNOON. AS THIS DISTURBANCE CONTINUES TO MOVE EAST INTO NORTH ALABAMA...THUNDERSTORMS WILL DECREASE IN COVERAGE TONIGHT. MEANWHILE...A WEAK FRONTAL BOUNDARY WAS LOCATED JUST NORTH OF THE FORECAST AREA. AS IT BEGIN TO MOVE NORTH TONIGHT...SOME ADDITIONAL THUNDERSTORMS MAY MOVE INTO NORTHWEST SECTIONS OF THE FORECAST AREA OVERNIGHT. AS THE FRONT MOVES NORTH TUESDAY...THE CHANCE OF THUNDERSTORMS WILL BE CONFINED TO MAINLY NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA. TEMPERATURES WILL START TO BECOME QUITE WARM ON TUESDAY WITH HIGHS IN THE LOW TO MID 90S. BY WEDNESDAY...AN UPPER LEVEL RIDGE WILL START TO BUILD INTO THE SOUTHEAST AND SOUTH CENTRAL U.S. THIS WILL BRING AN EXTENDED PERIOD OF DRY WEATHER TO THE FORECAST AREA WITH NO RAIN EXPECTED FROM WEDNESDAY THROUGH NEXT MONDAY. IN ADDITIONAL...TEMPERATURES WILL BE AS HOT IF NOT HOTTER THAN WE HAVE SEEN THIS SUMMER WITH HIGH TEMPERATURES IN THE MID TO UPPER 90S FROM WEDNESDAY THROUGH NEXT MONDAY. HEAT INDEX VALUES MAY EXCEED 105 AT TIMES DURING THIS PERIOD SO THERE MAY BE A NEED FOR A HEAT ADVISORY LATER THIS WEEK. ARS && .AVIATION... VFR CONDS ACROSS THE REGION ATTM. PATCHY FOG WILL DEVELOP LATER TONIGHT. LOW CLOUDS ARE POSSIBLE AT KMKL AND KTUP TUESDAY MORNING THOUGH CONFIDENCE IS TOO LOW FOR A BKN DECK ATTM. UPPER RIDGE WILL START BUILDING IN ON TUESDAY AND AREAL COVERAGE OF SHRAS/TSRAS WILL BE TOO LOW TO MENTION VCTS. WINDS WILL BE LIGHT OVERNIGHT AND WSW 7-10 KTS ON TUESDAY DIMINISHING AFTER SUNSET. SJM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1130 PM CDT MON AUG 18 2014 .AVIATION... /06Z TAFS/ Convective activity has moved out of the area. VFR ceilings will continue over all terminals through next 24 hours. Isolated thunderstorms will be possible over the area through the next 24 hours, however the coverage does not warrant their inclusion in the TAFs at this time. Due to the amount of rainfall that fell over the southern terminals during the last 24 hours, MVFR visibilities are likely to develop over the southern terminals before sunrise, improving to VFR by mid-morning. && .PREV DISCUSSION... /ISSUED 615 PM CDT MON AUG 18 2014/ .AVIATION... /00Z TAFS/ As of 6 pm, there is an area of widespread rainfall with embedded thunderstorms south of KABI and KSJT and affecting only the southern terminals. VFR conditions are expected to continue through the next 24 hours at all terminals. Isolated to scattered thunderstorms are possible through mid-evening over the southern terminal. Any thunderstorms that occur will be capable of producing variable and gusty winds. Thunderstorms are expected to occur again Tuesday morning, mainly over the southern terminals. && .PREV DISCUSSION... /ISSUED 350 PM CDT MON AUG 18 2014/ .SHORT TERM... (Tonight and Tuesday) Low confidence forecast across West Central Texas for the next 24 hours. Remnant Mesoscale Convective Vortex (MCV) continues to remain nearly stationary across Sterling County early this afternoon, and buried within a larger scale mid level shear axis stretching across much of the area. Much like we saw on Sunday, as the main morning area of showers and storms slowly winds down from Abilene to Brownwood, more scattered convection is developing along the periphery of the MCV where better heating is taking place. Biggest question in the forecast concerns tonight and Tuesday rain chances. As the low level jet intensifies towards midnight, expect to see another round of showers and storms form near the center of the MCV and along its eastern flank. MCV is definitely weaker today than it was yesterday, and should continue to slowly wind down. How strong it remains tonight, where it ends up, and what kind of storm coverage it can actually generate is highly uncertain though. Models not a lot of help, with even the TTU WRF and the HRRR models struggling in this highly mesoscale situation. At this point, will bump pops to chance for most of the area, knowing that some areas may miss out and others may see some decent rainfall. Some of this area has seen rainfall totals in the 1 to 3 inch range, so if the rain can train over these areas, than a flood threat becomes more pronounced. This will need to be monitored through tonight. 07 .LONG TERM... (Tuesday night through next Monday) A mainly dry forecast expected for the extended period. By Tuesday evening...the 500mb ridge that is currently centered near Florida will expand farther west into Texas, pushing the shear axis over the top of our CWA farther west as well. In addition, by Tuesday night, 250mph ridging will move in over the top of the region out of the southwest. These two factors point to decreasing chances of precipitation overall for the area by Tuesday night. However, we have left an area of slight chance PoPs in for Tuesday evening. The combination of the previously mentioned upper level shear axis and MCV is expected to result in additional thunderstorm activity tomorrow afternoon. And although these features are expected to be drifting to the west, there could still be lingering activity for areas mainly south and west of a Sterling City to San Angelo to Sonora line. By Wednesday, upper level ridging will be in place across our forecast area, effectively ending rain chances through the end of the forecast period, and allowing temperatures to remain warm in the mid to upper 90s for highs, and generally lower to mid 70s for lows. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 72 94 71 97 74 / 30 30 5 5 5 San Angelo 71 93 72 95 74 / 30 30 10 5 5 Junction 73 92 73 93 73 / 30 30 10 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
411 AM CDT TUE AUG 19 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 411 AM CDT TUE AUG 19 2014 AREAS OF DENSE FOG HAVE DEVELOPED OVER PORTIONS OF CENTRAL WISCONSIN EARLY THIS MORNING. A DENSE FOG ADVISORY HAS BEEN ISSUED FOR JACKSON...CLARK...AND TAYLOR COUNTIES WHERE THE VISIBILITY HAS FALLEN TO 1/4 MILE OR LESS. LOOK FOR THIS FOG TO DISSIPATE BETWEEN 8 AND 9 AM THIS MORNING. LATEST WATER VAPOR IMAGERY SHOWED A VIGOROUS UPPER LEVEL TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY...PUSHING SOUTHEAST. SHOWERS AND THUNDERSTORMS HAVE MOVED EAST OF THE FORECAST AREA EARLY THIS MORNING. THE TROUGH WILL CONTINUE TO SWING ACROSS THE AREA TODAY AND IS EXPECTED TO GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. NAM FORECAST SOUNDINGS SHOW TALL SKINNY CAPE PROFILES TODAY WITH ONLY 400-500 J/KG OF SBCAPE NOTED. MESOSCALE MODELS ARE REALLY NOT GENERATING MUCH CONVECTION THIS AFTERNOON...MAINLY SHOWING SCATTERED SHOWERS FOR LOCATIONS NORTH OF INTERSTATE 90. AFTER WE DESTABILIZE LATE THIS MORNING INTO THIS AFTERNOON WE SHOULD SEE THE SCATTERED SHOWERS AND ISOLATED STORMS DEVELOP. THIS ACTIVITY WILL THEN TAPER OFF LATE THIS AFTERNOON INTO THIS EVENING WITH THE LOSS OF DAYTIME HEATING. PLAN ON HIGHS TODAY RANGING FROM THE LOWER 70S OVER NORTH CENTRAL WISCONSIN TO THE UPPER 70S ACROSS NORTHEAST IOWA. FOCUS TURNS TO DENSE FOG POTENTIAL LATE TONIGHT INTO WEDNESDAY MORNING...ESPECIALLY ALONG VALLEY LOCATIONS. SURFACE HIGH PRESSURE SETTLES OVER THE FORECAST AREA LATE TONIGHT SETTING THE STAGE FOR LIGHT WINDS FROM THE SURFACE THROUGH 4 KFT. WITH SKIES BECOMING MOSTLY CLEAR AND DEW POINTS IN THE UPPER 50S TO LOWER 60S WE SHOULD SEE AREAS OF DENSE FOG DEVELOP. ALSO...THE NAM FORECAST SOUNDING AT KLSE LOOKS VERY FAVORABLE FOR A VALLEY FOG EVENT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 411 AM CDT TUE AUG 19 2014 AFTER SOME MORNING FOG...PARTLY TO MOSTLY SUNNY SKIES WILL BE THE RULE ACROSS THE AREA ON WEDNESDAY AS LOW PRESSURE LIFTS NORTH OUT OF THE CENTRAL PLAINS. THE LOW WILL PUSH A WARM FRONT INTO THE FORECAST AREA WEDNESDAY NIGHT INTO THURSDAY MORNING...BRINGING A VERY JUICY AIRMASS INTO THE REGION. PRECIPITABLE WATER VALUES INCREASE TO 1.8 TO 2.1 INCHES AND WARM CLOUD DEPTH TO 4.4 KM. THE STORMS DURING THIS TIMEFRAME. A BAND OF SHOWERS AND THUNDERSTORMS LOOKS TO LIFT NORTHEAST ACROSS THE FORECAST AREA FROM LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THE THUNDERSTORMS WILL BE VERY EFFICIENT RAIN PRODUCERS AND COULD DROP 1 TO 2 INCHES OF RAINFALL IN A SHORT AMOUNT OF TIME. THE WHOLE SYSTEM IS PROGRESSIVE SO THIS SHOULD LIMIT FLOODING CONCERNS BUT GIVEN THE AIRMASS CANNOT RULE OUT NEEDING SOME HYDROLOGY HEADLINES WEDNESDAY NIGHT INTO TUESDAY MORNING. THE SHOWERS AND STORMS SHOULD LIFT NORTHEAST THROUGH THE DAY ON THURSDAY LEAVING A VERY HUMID AIRMASS ACROSS THE FORECAST AREA IN THE WAKE OF THIS ACTIVITY. BEYOND THURSDAY THE FORECAST BECOMES CHALLENGING WITH MODELS IN DISAGREEMENT ON HOW MUCH RIDGING BUILDS INTO THE FORECAST AREA. THE ECMWF IS THE MOST AGGRESSIVE AND BUILDS HEAT ACROSS THE AREA GOING INTO THIS WEEKEND. THE GFS KEEPS THE WARM FRONT LINGERING OVER THE FORECAST AREA ON FRIDAY WITH CONTINUE CHANCES FOR HEAVY RAINFALL. A HOT AIRMASS IS FOCUSED JUST SOUTH OF THE AREA GOING INTO THIS WEEKEND AND IT WOULD TAKE MUCH TO GET THE STEAMY AIR INTO NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN SO WILL HAVE TO KEEP A VERY CLOSE EYE ON HOW MUCH RIDGING CAN BUILD OVER THE AREA...AND WHERE THE FRONT SETS UP. CONVECTION WILL HAVE A HUGE IMPACT ON TEMPERATURES AND THE LOCATION OF THE BOUNDARY. COOLER AIR THEN LOOKS RETURN EARLY NEXT WEEK AS THE BOUNDARY IS PUSHED TO THE SOUTH OF THE UPPER MISSISSIPPI RIVER VALLEY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1157 PM CDT MON AUG 18 2014 MAIN AREA OF CONVECTION HAS PASSED BY BOTH TAF SITES. THE WIND SHIFT HAS YET TO COME THROUGH AND BASED ON THE 19.03Z RAP THIS SHOULD PASS THROUGH LATE TONIGHT SWINGING THE WINDS AROUND TO THE WEST AND THEN NORTHWEST. THE RAP BUFKIT SOUNDING ALSO NOW SHOWS LITTLE POTENTIAL FOR SATURATION TO OCCUR BEHIND THE BOUNDARY MAKING IT LOOK LESS LIKELY THAT FOG AND LOW LEVEL STRATUS WILL FORM. GIVEN THAT BOTH SITES DID HAVE RAIN TONIGHT...WILL LEAVE SOME MVFR VISIBILITIES IN THE FORECASTS IN THE EVENT THAT THE WINDS DROP OFF SOME BEHIND THE FRONT. WITH ALL THE LOW LEVEL MOISTURE FROM THE RAIN AND AS SOME HEATING STARTS AFTER SUNRISE...DO EXPECT TO SEE SOME MVFR CEILINGS FORM BY MID MORNING AND THE PERSIST INTO THE EARLY AFTERNOON BEFORE THESE LIFT TO VFR. THESE CEILINGS SHOULD THEN REMAIN THROUGH THE AFTERNOON BEFORE SCATTERING OUT LATE IN THE AFTERNOON OR EARLY EVENING. && .HYDROLOGY...WEDNESDAY NIGHT INTO THURSDAY ISSUED AT 411 AM CDT TUE AUG 19 2014 THERE IS THE POTENTIAL FOR THUNDERSTORMS WITH HEAVY RAINFALL WEDNESDAY NIGHT INTO THURSDAY MORNING. THESE STORMS COULD PRODUCE 1 TO 2 INCHES OF RAINFALL WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS RAINFALL COMBINED WITH RECENT HEAVY RAINS ACROSS PORTIONS OF THE FORECAST AREA COULD LEAD TO FLOODING CONCERNS. A FLASH FLOOD WATCH MAY BE NEEDED WEDNESDAY NIGHT INTO THURSDAY MORNING ONCE CONFIDENCE INCREASES ON EXACTLY WHERE THE HEAVIER RAINFALL WILL OCCUR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ017-029- 034. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04 HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1157 PM CDT MON AUG 18 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 315 PM CDT MON AUG 18 2014 FORECAST FOCUS IS ON RAIN TONIGHT AS UPPER SHORT WAVE PASSES THROUGH THE REGION WITH A WARM AND HUMID AIRMASS IN PLACE. A CLOSED LOW CUTS OFF OVER THE GREAT LAKES AS THIS WAVE ROUNDS THE BASE OF THE LONG WAVE TROUGH. WITH WEAKER IMPULSES CIRCULATING AROUND THE LOW...RAIN CHANCES LINGER INTO TUESDAY AS WELL. 19Z MESOANALYSIS SHOWS UPPER WAVE SPINNING INTO NORTHWEST MN... HEADING SOUTHEAST. PLUME OF 70+ LOW LEVEL DEWPOINTS FROM EASTERN IA UP INTO WESTERN WI AHEAD OF THE APPROACHING WAVE. ACTIVE CONVECTION ONGOING FROM WEST CENTRAL INTO NORTHEAST WI...AND NEW ACTIVITY GOING UP OVER NORTHEAST IA AND SOUTHEAST MN. ANTICIPATE SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT...WITH PERHAPS A BREAK FOR A TIME EARLY THIS EVENING AFTER THIS FIRST INITIAL BAND. PRECIPITABLE WATER SOMEWHAT ELEVATED AND WARM CLOUD DEPTH 3500+ METERS. ANY STORMS WILL BE PRODUCING HEAVY DOWNPOURS. DCAPE SUGGESTS WIND POTENTIAL AS WELL. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 315 PM CDT MON AUG 18 2014 UPPER LEVEL LOW OVER THE GREAT LAKES SHIFTS EAST ON WEDNESDAY AS UPPER RIDGING BUILDS INTO THE UPPER MIDWEST. A PATTERN SHIFT TO MORE SOUTHWEST FLOW TAKES PLACE MID-WEEK WITH A LONG WAVE TROUGH ESTABLISHING ITSELF OVER THE WESTERN CONUS. EVENTUAL RAIN CHANCES LATER THIS WEEK...AND THE DEGREE OF WARMING...ARE TIED TO HOW THE SHORT WAVE TROUGH ENERGY EJECTS NORTHEAST TOWARD OUR REGION. MEDIUM RANGE MODELS DO SHOW SOME DIFFERENCES IN TIMING OF THESE IMPULSES...SO CONFIDENCE NOT HIGH. BUT IT DOES APPEAR THE OVERALL TREND OF WARM AND HUMID CONDITIONS WILL COME TO FRUITION. IT HAS BEEN DRY LATELY...BUT THESE STORMS ONCE AGAIN LOOK TO HAVE INGREDIENTS FOR HEAVY RAIN POTENTIAL. THIS WILL HAVE TO BE MONITORED AS WE START TO ACCUMULATE SOME RAINFALL ON OUR RECENTLY DRY SOILS...WILL A FLOOD WATCH EVENTUALLY BE NECESSARY? && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1157 PM CDT MON AUG 18 2014 MAIN AREA OF CONVECTION HAS PASSED BY BOTH TAF SITES. THE WIND SHIFT HAS YET TO COME THROUGH AND BASED ON THE 19.03Z RAP THIS SHOULD PASS THROUGH LATE TONIGHT SWINGING THE WINDS AROUND TO THE WEST AND THEN NORTHWEST. THE RAP BUFKIT SOUNDING ALSO NOW SHOWS LITTLE POTENTIAL FOR SATURATION TO OCCUR BEHIND THE BOUNDARY MAKING IT LOOK LESS LIKELY THAT FOG AND LOW LEVEL STRATUS WILL FORM. GIVEN THAT BOTH SITES DID HAVE RAIN TONIGHT...WILL LEAVE SOME MVFR VISIBILITIES IN THE FORECASTS IN THE EVENT THAT THE WINDS DROP OFF SOME BEHIND THE FRONT. WITH ALL THE LOW LEVEL MOISTURE FROM THE RAIN AND AS SOME HEATING STARTS AFTER SUNRISE...DO EXPECT TO SEE SOME MVFR CEILINGS FORM BY MID MORNING AND THE PERSIST INTO THE EARLY AFTERNOON BEFORE THESE LIFT TO VFR. THESE CEILINGS SHOULD THEN REMAIN THROUGH THE AFTERNOON BEFORE SCATTERING OUT LATE IN THE AFTERNOON OR EARLY EVENING. && .HYDROLOGY... ISSUED AT 315 PM CDT MON AUG 18 2014 SO FAR IN AUGUST...OVERALL IT HAS BEEN QUITE DRY WITH MUCH OF THE AREA ADDED TO THE ABNORMALLY DRY CATEGORY PER THE DROUGHT MONITOR. BUT AS WE SAW LAST NIGHT...SLOW MOVING STORMS PRODUCING TORRENTIAL DOWNPOURS CAN RESULT IN SOME LOCALIZED FLOODING ISSUES. ONCE AGAIN TONIGHT...WARM CLOUD DEPTH AND ELEVATED PRECIPITABLE WATER AMOUNTS POINT TO HEAVY RAINFALL POTENTIAL. THIS TREND LOOKS TO CONTINUE THROUGH MUCH OF THE WEEK AS WELL. DRY CONDITIONS INITIALLY WILL ALLOW FOR MUCH OF THIS WATER TO BE UTILIZED BY THE SOIL AND REPLENISHING STORAGE AREAS. BUT WE WILL HAVE TO MONITOR THE RAINFALL OVER THE COMING DAYS AND PERHAPS CONSIDER THE NEED FOR A FLOOD WATCH FOR AREAS THAT SEE REPEATED RAINFALL. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...MW LONG TERM...MW AVIATION...04 HYDROLOGY...MW
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
940 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER TROUGH AND STRONG HEATING WILL SUPPORT SCATTERED THUNDERSTORMS THIS AFTERNOON INTO THE EVENING. DRIER AIR AND A BUILDING UPPER RIDGE JUST TO OUR WEST WILL REDUCE THUNDERSTORM CHANCES WEDNESDAY AND THURSDAY...AND LEAD TO HOTTER HIGH TEMPERATURES. AN APPROACHING COLD FRONT AND INCREASING MOISTURE WILL INCREASE THE THUNDERSTORM CHANCE OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TODAY...SCATTERED SHOWERS WERE MOVING INTO THE AREA THIS MORNING ASSOCIATED WITH LIFT AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE TROUGH PLUS HEATING AND CONVERGENCE INTO THE LEE-SIDE SURFACE TROUGH SHOULD HELP SUPPORT THUNDERSTORMS LATER TODAY. THE HIGH RESOLUTION MODELS INDICATE SCATTERED COVERAGE. THE COVERAGE WILL PROBABLY REMAIN LIMITED BECAUSE MUCH OF THE UPPER-LEVEL LIFT AHEAD OF THE SHORTWAVE TROUGH WILL LIKELY OCCUR EARLY AND BEFORE MAXIMUM HEATING. ALSO...CONVERGENCE INTO THE SURFACE FEATURE SHOULD REMAIN WEAK AND FORECAST SOUNDINGS SHOW WESTERLY FLOW THROUGH A DEEP LAYER WHICH SHOULD HELP KEEP MOISTURE SOMEWHAT SHALLOW. SIGNIFICANT UNI-DIRECTIONAL WIND SHEAR WITH 5000-FOOT WINDS NEAR 30 KNOTS MAINLY IN THE SOUTH PART AND STEEP LOW-LEVEL LAPSE RATES MAY HELP SUPPORT STRONG WIND GUSTS WITH ANY THUNDERSTORMS. STRONG MIXING WILL BRING GUSTY WINDS. USED THE GFS LAMP AND NAM BUFKIT MOMENTUM-TRANSFER TOOL FOR THE WIND GUST FORECAST. USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF THE WESTERLY FLOW. TONIGHT...THE MODELS MAINTAIN SURFACE TROUGHING. HOWEVER...BELIEVE THE THUNDERSTORM CHANCE IS LOW BECAUSE OF SHALLOW MOISTURE IN THE WAKE OF THE MID-LEVEL SHORTWAVE TROUGH AND NOCTURNAL COOLING. THE NAM AND GFS MOS HAVE POPS 20 TO 30 PERCENT...MAINLY IN THE EVENING CLOSER TO THE TIME OF HEATING. THE TEMPERATURE GUIDANCE WAS CLOSE. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... UPPER RIDGE WILL BUILD JUST TO OUR WEST WEDNESDAY AS THE UPPER TROUGH MOVES OFF THE COAST. WARMING 850MB TEMPERATURES AND A LOW LEVEL DOWNSLOPE FLOW WILL RESULT IN MAX TEMPERATURES PUSHING 100 DEGREES WEDNESDAY AND THURSDAY. GUIDANCE INDICATES DEW POINTS MIXING DOWN INTO THE MID TO UPPER 60S ACROSS THE NORTHERN AND WESTERN COUNTIES TO NEAR 70 ACROSS THE SOUTHEAST MIDLANDS. THIS SHOULD KEEP HEAT INDICES JUST BELOW OUR HEAT ADVISORY CRITERIA OF 110F. ONLY SLIGHT CHANCE OF SHOWERS/TSTMS EXPECTED BOTH WEDNESDAY AND THURSDAY DUE TO DRIER AIR AND BUILDING RIDGE ALOFT. && .LONG TERM /FRIDAY THROUGH MONDAY/... UPPER RIDGE TO OUR WEST WITH UPPER TROUGH AND CLOSED LOW TO OUR NE...PROVIDING A NW FLOW ALOFT FOR OUR FA. SOME TIMING UNCERTAINTIES...BUT MODELS SUGGEST A BACK DOOR FRONT WILL MOVE DOWN THE EAST COAST...REACHING OUR FA SOME TIME THIS WEEKEND. THIS WOULD INCREASE POPS ALONG AND SOUTH OF THE BOUNDARY...AND LEAD TO COOLER TEMPS NORTH OF IT. WILL MAINTAIN TREND IN THE ONGOING FORECAST OF POPS TRENDING HIGHER AND TEMPS TRENDING LOWER DURING THAT TIME. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. CLOUDINESS ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH AND H85 WIND SPEED CONVERGENCE MAY BRING A PERIOD OF MVFR CEILINGS AT SOME OF THE TAF SITES. HEATING AND MIXING SHOULD HELP DIMINISH THIS CLOUDINESS BY MIDDAY. SATELLITE TRENDS AND THE HRRR GUIDANCE INDICATED A PERIOD OF MVFR AT AGS...DNL...CAE...AND CUB. SCATTERED SHOWERS WERE MOVING INTO THE AREA THIS MORNING ASSOCIATED WITH LIFT AHEAD OF THE MID-LEVEL SHORTWAVE TROUGH. THE TROUGH PLUS HEATING AND CONVERGENCE INTO THE LEE-SIDE SURFACE TROUGH SHOULD HELP SUPPORT THUNDERSTORMS LATER TODAY. THE HIGH RESOLUTION MODELS INDICATE SCATTERED COVERAGE. THE COVERAGE WILL PROBABLY REMAIN LIMITED BECAUSE MUCH OF THE UPPER-LEVEL LIFT AHEAD OF THE SHORTWAVE TROUGH WILL LIKELY OCCUR EARLY AND BEFORE MAXIMUM HEATING. ALSO...CONVERGENCE INTO THE SURFACE FEATURE SHOULD REMAIN WEAK AND FORECAST SOUNDINGS SHOW WESTERLY FLOW THROUGH A DEEP LAYER WHICH SHOULD HELP KEEP MOISTURE SOMEWHAT SHALLOW. THE THUNDERSTORM CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME BECAUSE OF THE SCATTERED COVERAGE AND TIMING UNCERTAINTY. SIGNIFICANT UNI-DIRECTIONAL WIND SHEAR WITH 5000-FOOT WINDS NEAR 30 KNOTS MAINLY IN THE SOUTH PART AND STEEP LOW-LEVEL LAPSE RATES MAY HELP SUPPORT STRONG WIND GUSTS NEAR ANY THUNDERSTORMS. STRONG MIXING WILL BRING GUSTY WINDS. USED THE GFS LAMP AND NAM BUFKIT MOMENTUM-TRANSFER TOOL FOR THE WIND GUST FORECAST. DRYING ALOFT AND LINGERING LOW-LEVEL MOISTURE PLUS NOCTURNAL COOLING MAY HELP SUPPORT FOG TONIGHT. MOST OF THE NAM AND GFS MOS INDICATE MVFR FOG. FOG WILL LIKELY BE LIMITED BY SOME MIXING. EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING FOG THROUGH THE PERIOD. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
808 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER TROUGH AND INCREASING MOISTURE WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS TODAY. DRIER AIR AND A BUILDING UPPER RIDGE JUST TO OUR WEST WILL REDUCE AFTERNOON THUNDERSTORM CHANCES WEDNESDAY AND THURSDAY...AND LEAD TO INCREASING HIGH TEMPERATURES. AN APPROACHING BACKDOOR FRONT AND INCREASING MOISTURE WILL LEAD TO GREATER THUNDERSTORM CHANCES OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... A SHORTWAVE TROUGH CROSSING NORTHERN GA IN NEAR ZONAL FLOW THIS MORNING IS EXPECTED TO MOVE INTO WESTERN SC AROUND SUNRISE AND CROSS THE FORECAST AREA TODAY. HAVE INCREASED POPS TO THE 40 TO 50 PERCENT RANGE. WEAK TO MODERATE INSTABILITY IS FORECAST ALONG WITH PWAT INCREASING TO AROUND OR ABOVE 2.00 INCHES THIS AFTERNOON. CANNOT RULE OUT AN ISOLATED STRONG TO SEVERE STORM THIS AFTERNOON GIVEN INVERTED V SIGNATURE INDICATED IN FORECAST SOUNDINGS FOR THE AFTERNOON. DAMAGING WIND GUSTS WOULD BE THE MAIN THREAT IF A SEVERE STORM DEVELOPS WITH LARGE HAIL GENERALLY UNLIKELY DUE TO FREEZING LEVEL HEIGHT OVER 15KFT. THE CENTRAL AND SOUTHEASTERN MIDLANDS AND CSRA LOOK TO BE THE MOST FAVORABLE LOCATION FOR STORMS TODAY. KEPT AFTERNOON HIGHS ON THE WARM SIDE OF GUIDANCE. CONVECTION WILL DECREASE EARLY THIS EVENING AS THE SHORT WAVE MOVES EAST OF THE AREA. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO THE LOWER 70S AS SKIES BECOME MOSTLY CLEAR. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... UPPER RIDGE WILL BUILD JUST TO OUR WEST WEDNESDAY AS THE UPPER TROUGH MOVES OFF THE COAST. WARMING 850MB TEMPERATURES AND A LOW LEVEL DOWNSLOPE FLOW WILL RESULT IN MAX TEMPERATURES PUSHING 100 DEGREES WEDNESDAY AND THURSDAY. GUIDANCE INDICATES DEWPOINTS MIXING DOWN INTO THE MID TO UPPER 60S ACROSS THE NORTHERN AND WESTERN COUNTIES TO NEAR 70 ACROSS THE SOUTHEAST MIDLANDS. THIS SHOULD KEEP HEAT INDICES JUST BELOW OUR HEAT ADVISORY CRITERIA OF 110F. ONLY SLIGHT CHANCE OF SHOWERS/TSTMS EXPECTED BOTH WEDNESDAY AND THURSDAY DUE TO DRIER AIR AND BUILDING RIDGE ALOFT. && .LONG TERM /FRIDAY THROUGH MONDAY/... NO SIGNIFICANT CHANGES MADE TO THE LONG TERM FORECAST. PREVIOUS DISCUSSION: UPPER RIDGE TO OUR WEST WITH UPPER TROUGH AND CLOSED LOW TO OUR NE...PROVIDING A NW FLOW ALOFT FOR OUR FA. SOME TIMING UNCERTAINTIES...BUT MODELS SUGGEST A BACK DOOR FRONT WILL MOVE DOWN THE EAST COAST...REACHING OUR FA SOME TIME THIS WEEKEND. THIS WOULD INCREASE POPS ALONG AND SOUTH OF THE BOUNDARY...AND LEAD TO COOLER TEMPS NORTH OF IT. WILL MAINTAIN TREND IN THE ONGOING FORECAST OF POPS TRENDING HIGHER AND TEMPS TRENDING LOWER DURING THAT TIME. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. H85 WIND SPEED CONVERGENCE MAY HELP SUPPORT A PERIOD OF MVFR CEILINGS THIS MORNING. THE 08Z HRRR INDICATED MVFR CEILINGS FOR A SHORT PERIOD OF TIME THIS MORNING AT AGS AND DNL. HEATING AND MIXING SHOULD HELP DIMINISH THIS CLOUDINESS LATER THIS MORNING. SCATTERED SHOWERS WERE MOVING INTO THE AREA THIS MORNING ASSOCIATED WITH LIFT AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE TROUGH PLUS HEATING AND CONVERGENCE INTO THE LEE-SIDE SURFACE TROUGH SHOULD HELP SUPPORT THUNDERSTORMS LATER TODAY. THE HIGH RESOLUTION MODELS INDICATE SCATTERED COVERAGE. THE COVERAGE WILL PROBABLY REMAIN LIMITED BECAUSE MUCH OF THE UPPER-LEVEL LIFT AHEAD OF THE SHORTWAVE TROUGH WILL LIKELY OCCUR EARLY BEFORE MAXIMUM HEATING. ALSO...CONVERGENCE INTO THE SURFACE FEATURE SHOULD REMAIN WEAK AND FORECAST SOUNDINGS SHOW WESTERLY FLOW THROUGH A DEEP LAYER WHICH SHOULD HELP KEEP MOISTURE SOMEWHAT SHALLOW. THE THUNDERSTORM CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME BECAUSE OF THE SCATTERED COVERAGE AND TIMING UNCERTAINTY. SIGNIFICANT UNI-DIRECTIONAL WIND SHEAR WITH 5000-FOOT WINDS NEAR 30 KNOTS MAINLY IN THE SOUTH PART AND STEEP LOW-LEVEL LAPSE RATES MAY HELP SUPPORT STRONG WIND GUSTS NEAR ANY THUNDERSTORMS. STRONG MIXING WILL BRING GUSTY WINDS. USED THE GFS LAMP AND NAM BUFKIT MOMENTUM-TRANSFER TOOL FOR THE WIND GUST FORECAST. EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE NIGHT AND EARLY MORNING FOG THROUGH THE PERIOD. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 923 AM CDT Tue Aug 19 2014 .UPDATE... ISSUED AT 923 CDT TUE AUG 19 2014 Area of showers and thunderstorms associated with an upper-level wave is currently crossing the Mississippi River into west-central Illinois. 1417z radar imagery shows leading edge of precip extending from Galesburg...to Rushville...to Bowling Green Missouri. Based on timing tools, showers/thunder will arrive along the I-55 corridor by midday. HRRR and other high-res models generally show the precip area weakening as it pushes eastward through the morning, then potentially re-developing across east-central Illinois later this afternoon. Made some adjustments to hourly PoPs today, mainly to increase to categorical along/west of I-55 during the morning. Once the wave passes, rain chances will come to an end across the Illinois River Valley by mid to late afternoon, followed by a return to partly to mostly sunny skies. Further east, rain chances will linger throughout the day before coming to an end by evening. && .SHORT TERM...(This afternoon through Wednesday) ISSUED AT 336 AM CDT TUE AUG 19 2014 Short term models have trended slower with the front and precip that is currently supposed to be moving into the area. But will still have chance of precip starting in the northwest parts of the cwa this morning. Then will progress the pcpn chances southeastward across the cwa during the day. By this evening, most of the pcpn will be in the eastern two thirds of the area with the highest pops in the southeast. By overnight, the pcpn should have moved southeast of the area so most of the area should be dry overnight, though will keep a slight chance of pops in the southeast after midnight. Could be some additional pcpn in the southwest late tonight, but models keep most of pcpn west of the area through 12z. Temps will begin the slow warming tomorrow, and am expecting mid to upper 80s throughout the area today. && .LONG TERM...(Wednesday night through Monday) ISSUED AT 347 AM CDT TUE AUG 19 2014 Models still pretty consistent with the development and lift of a boundary through the Midwest on Wednesday. Boundary will have little reflection at the sfc with very weak flow/weak wind shift, and thermal gradient is better represented in the mid levels. Boundary will provide a weak focus for waves moving through the region as the boundary lifts to the NE through the area for Wed/Wed night. Though Wed is lacking signif pop for now, the timing of the progression is better for early evening and into the overnight on Wednesday night/shifting to the northeast for Thurs. Position of the boundary or the remnants thereof will be where the majority of the precip chances will be...increasing to the north, particularly north of Interstate 74 from Thursday to Saturday. Ample sfc based instability in the form of hot and humid conditions as the ridge over the southwest opens and spreads signif heat into the Midwest. Models have also shown consistency with 850 mb temps in the 19-25C range from Wednesday through Sunday. This will drive the temps into the upper 80s/lower 90s with heat indices in the upper 90s/approaching 100F. A far more summer-like pattern than much of the season so far, and well above normal for this time of year...with breaks from the heat provided by any thunderstorms that may have the chance to form from more diurnal instability with any frontal forcing further to the north. Into the extended, day 7/just into day 8, models diverge in solutions with major difference in breaking down the upper ridge for the Midwest. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) ISSUED AT 609 AM CDT TUE AUG 19 2014 Cold front is still back northwest of the area, but still forecasted to move through the area, affecting all TAF sites this through afternoon. However, radar loops show a complex of thunderstorms in northern MO that could move into central IL this morning and effect some of the TAF sites, possibly SPI and DEC. Short term models do show some pcpn moving through the area this morning, but appears it will diminish as it moves into the area. Then the front drops into the area a few hours later and this will bring a chance of thunderstorms to the TAF sites for the afternoon and early evening. The early stuff could be just showers, but since the front will be right on the heels of the current complex coming out of MO, will opt to just have VCTS for all TAFs to cover both events. Believe t-storms will be more scattered as well. Also VCTS will be in the TAFs longer than necessary, but only because of two events. Not expecting cigs to go down today, but having some light fog issues at mainly CMI, with some very light fog at PIA and BMI. This fog will burn off quickly, like yesterday morning. Winds will be south to southwest through the morning and then become southwest just ahead of the front, and then westerly or light and variable after FROPA. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...AUTEN LONG TERM...HJS AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
651 AM CDT TUE AUG 19 2014 .AVIATION... CONCERNING THE ARKLATEX...A LOT OF DEBRIS CIRRUS KEEPING STATION AND MITIGATING MVFR BOTH CIGS/FG. CONVECTION TODAY MAY OCCUR OVER THE SOUTH WITH RESPECT TO A WEAK SEA BREEZE PUSH AND OVER OUR NORTH ALONG A WEAK SHEAR AXIS WITH SOMEWHAT BETTER CHANCES FROM KTXK...TO KMLU AND MAY BRIEFLY AFFECT KELD AND KSHV THIS MID AFTERNOON BASED ON THE HIGH RES MODEL. VCTS FOR THE AFTERNOON HOURS WILL BE AMENDED WITH DEVELOPMENT. OTHERWISE S/SW WINDS ON THE SFC ARE GENERALLY SW- NW ALOFT WITH NOT MUCH SPEED ANYWHERE. /24/ && .PREV DISCUSSION... /ISSUED 423 AM CDT TUE AUG 19 2014/ DISCUSSION... THE MORNING WATER VAPOR IMAGERY INDICATES THAT THE MAIN SHORTWAVE THAT PRODUCED EXTENSIVE CONVECTION JUST 24 HRS AGO OVER SW AR/EXTREME NRN LA HAS SHIFTED E INTO NRN GA...WITH THE 00Z RAOB 500MB PLOT STILL REVEALING A WEAK SHEAR AXIS THAT EXTENDS FARTHER W ACROSS NRN MS/N LA AND INTO NE TX. MEANWHILE...MOSAIC RADAR IMAGERY ALSO INDICATES A WELL-DEFINED MCV SPINNING E OF SJT...WHICH THE 00Z PROGS HAVE INITILIZED WELL ON AS CONVECTION CONTINUES TO REGENERATE NEAR AND E OF THE CENTER OVER CNTRL TX. THIS CONVECTION HAS PRODUCED A THICK AC CANOPY OVER NE TX/EXTREME NW LA...ALTHOUGH IR IMAGERY DEPICTS WARMING CLOUD TOPS SUGGESTING A WEAKENING TREND IS ONGOING ATTM. THIS MCV CENTER IS PROGGED TO DRIFT NNE ACROSS NCNTRL TX TODAY...WHICH COULD MAINTAIN ELEVATED CONVECTIVE DEBRIS OVER THE NRN HALF OF THE AREA THROUGH AT LEAST THE FIRST HALF OF THE DAY...BEFORE POSSIBLY THINNING THIS AFTERNOON. MY FORECAST MAX TEMPS MAY BE A BIT HIGH TODAY ESPECIALLY IF THIS DEBRIS FIELD HANGS TOUGH TODAY...BUT HAVE PLAYED THE PESSIMIST WITH IT THINNING LATER TODAY...ESPECIALLY AS 09Z TEMPS REMAIN IN THE MID/UPPER 70S. WHILE THE SHORT TERM PROGS DO SUGGEST A WEAK SEABREEZE AFFECTING DEEP E TX/SRN SECTIONS OF NCNTRL LA THIS AFTERNOON...ONLY THE LATEST HRRR RUN DEPICTS AT LEAST ISOLATED CONVECTION DEVELOPING THIS AFTERNOON ALONG THE RESIDUAL SHEAR AXIS...WHICH IS STILL WEAKLY REFLECTED IN THE OTHER SHORT RANGE PROGS. IN ADDITION...THE 09Z SFC ANALYSIS INDICATES A DISTINCT W-E GRADIENT IN SFC THETA-E FROM NEAR OSA TO ALONG THE AR/LA LINE...INDICATIVE OF THE WEAK COLD POOL FROM CONVECTION THAT AFFECTED THESE AREAS MONDAY AFTERNOON/EVENING. GIVEN THESE WEAK SFC AND UPPER AIR FORCING MECHINISMS...AND THE FACT THAT THE CNTRL TX MCV IS PROGGED TO LIFT NNE ACROSS THE STATE TODAY...HAVE EXPANDED SLIGHT CHANCE POPS TO COVER MUCH OF THE REGION THIS AFTERNOON...AND DID CARRY THEM THROUGH THE EVENING BEFORE THEY DIMINISH WITH THE STABILIZING BNDRY LYR. THE SHEAR AXIS IS EXPECTED TO WASH OUT OVERNIGHT WITH THE MCV OPENING UP LATE...AS THE WRN ATLANTIC/CNTRL GULF OF MX UPPER RIDGE EXPECTED TO BRIDGE NWD INTO THE LOWER MS VALLEY WEDNESDAY. STILL SHOULD SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES WEDNESDAY AND THURSDAY AFTERNOONS/EARLY EVENINGS...BEFORE THE UPPER RIDGE CENTER BECOMES ESTABLISHED OVER THE MID-SOUTH/LOWER MS VALLEY FRIDAY. BOTH THE GFS AND ECMWF AMPLIFY THE RIDGE FARTHER N ACROSS THE SRN PLAINS/MS VALLEY FRIDAY...AND KEEPS IT PERSISTENT THROUGH THE WEEKEND INTO EARLY NEXT WEEK. INCREASED SUBSIDENCE WILL RESULT IN MAX TEMPS CLIMBS INTO THE UPPER 90S AREAWIDE...WITH EVEN SOME TRIPLE DIGITS POSSIBLE OVER SOME AREAS THIS WEEKEND/EARLY NEXT WEEK. THE MEDIUM RANGE PROGS DO BEGIN TO SLOWLY NUDGE THE RIDGE E INTO THE SE STATES BY TUESDAY/WEDNESDAY...WITH WEAKNESSES RIDING W BENEATH THE RIDGE ACROSS S LA/SRN MS AS EARLY AS MONDAY. THUS...ISOLATED CONVECTION WILL BE POSSIBLE OVER NCNTRL LA MONDAY AFTERNOON...BEFORE SPREADING FARTHER WNW TO ENCOMPASS MUCH OF THE REGION BY THE END OF THE EXTENDED. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 96 76 97 / 10 10 10 10 10 MLU 95 73 96 74 97 / 20 20 10 10 10 DEQ 94 71 94 71 95 / 20 20 0 0 0 TXK 94 74 96 74 96 / 20 20 0 0 0 ELD 95 72 96 74 97 / 20 20 0 0 0 TYR 94 75 96 76 97 / 10 20 10 10 10 GGG 95 74 96 75 97 / 10 10 10 10 10 LFK 96 75 96 76 97 / 20 20 20 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 24
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1033 AM CDT TUE AUG 19 2014 .UPDATE...INCREASED POPS SLIGHTLY TO CARRY SLIGHT CHANCE THUNDERSTORM WORDING ACROSS NW LOCATIONS THROUGH 1PM GIVEN CURRENT RADAR TRENDS BUT ALSO CUT SOME FOR SW AREAS THROUGH THAT SAME TIME PERIOD. HOURLY TEMP/DEWPOINTS WERE ALTERED SLIGHTLY BUT MAINLY ON TRACK WITH LITTLE TO NO CHANGE IN EXPECTED HIGHS. .DISCUSSION...A FEW THUNDERSTORMS ARE ONGOING IN AR/TN MOVING INTO NORTH MS THIS HOUR. HI-RES MODELS ARE HAVING A HARD TIME RESOLVING THIS ACTIVITY BUT THE RAP DOES INDICATE SOME LOWER CONDENSATION PRESSURE DEFICITS IN CONJUNCTION WITH ISENTROPIC UPGLIDE AND STEEPER LAPSE RATES IN THE VICINITY OF THE CURRENT ACTIVITY. FOLLOWING THE RAP GUIDANCE, IT SUGGESTS A LOW-LVL CONVERGENCE AREA TO PROPAGATE OUT OF THIS CLUSTER (LIKELY FROM AN OUTFLOW BOUNDARY) THAT COULD ACT TO INITIATE NEW ACTIVITY THROUGH THE DAY AS INSTABILITY BUILDS. MICROBURST RISK REVEALED SUBSTANTIAL SBCAPE ABOVE 3000 J/KG BUT WITH PWATS UP NEAR 2" FEEL SCATTERED SHOWERS/STORMS WILL BEGIN BY EARLY AFTN SOUTH OF THIS CLUSTER. SOME STORMS COULD BECOME STRONG TO BRIEFLY SEVERE IF ORGANIZED ALONG A COLD POOL BUT OVERALL COVERAGE OF THESE HAZARDS WILL BE ISOLATED. WILL NOT INCLUDE ANY STRONG/SEVERE GRAPHIC UPDATES AT THIS TIME. COVERAGE SHOULD DIMINISH THROUGH THE EVENING AS THE RIDGE STRENGTHENS OVER THE REGION THROUGH THE NEXT SEVERAL DAYS. AN UPDATED AVIATION DISCUSSION CAN BE FOUND BELOW. /ALLEN/ && .AVIATION...A MIX OF MVFR/VFR FLIGHT CATEGORIES ARE BEING OBSERVED THIS MORNING AS LOW STRATUS HAS BEEN A LITTLE SLOWER TO ERODE THAN PREVIOUSLY ANTICIPATED. STILL...VFR CONDITIONS ARE EXPECTED AS WE MOVE INTO THE AFTERNOON HOURS WITH SCATTERED TO BROKEN CEILINGS BETWEEN 3000-5000 FEET EXPECTED...ALONG WITH SOME MID AND HIGH CLOUDS STREAMING OVERHEAD. SCATTERED CONVECTION IS AGAIN EXPECTED THROUGH THE AFTERNOON TODAY. THIS COULD RESULT IN A BRIEF PERIOD OF MVFR/IFR CEILINGS AND/OR VISIBILITIES IF CONVECTION IS OBSERVED WITHIN A TAF SITES RESPECTED AERODROME. SHOWERS AND STORMS WILL DISSIPATED THIS EVENING...WITH ANOTHER BOUT OF MVFR/IFR CEILINGS/VISIBILITIES POSSIBLE EARLY WEDNESDAY MORNING DUE TO LOW STRATUS AND/OR PATCHY FOG. WINDS TODAY WILL BE WEST SOUTHWESTERLY BETWEEN 5-10 KNOTS...AND WILL GRADUALLY SUBSIDE TO LIGHT TO CALM TONIGHT. /19/ && .PREV DISCUSSION... /ISSUED 403 AM CDT TUE AUG 19 2014/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...AS RIDGING CONTINUES OVER THE CENTER OF THE COUNTRY...THE ARKLAMISS REGION REMAINS UNDER NORTHWEST FLOW ALOFT. A TROUGH AXIS IS LOCATED ACROSS EASTERN MISSISSIPPI AND ALABAMA THIS MORNING AND WILL CONTINUE THERE TODAY. THIS SHOULD COMBINE WITH ENOUGH MOISTURE TO BRING SOME ADDITIONAL SHOWERS AND STORMS TODAY. WHILE SOME STORMS WILL BE POSSIBLE ACROSS WESTERN ZONES...HEIGHTS WILL BE RISING IN THIS REGION AND SHOULD WORK TO SUPPRESS CONVECTION A BIT MORE THERE. WHILE CONVECTION IN THIS NORTHWEST FLOW REGIME HAS NOT BEEN DEPICTED TERRIBLY WELL ON MODELS OF LATE...HI-RES MODELS AND EVEN THE LOCAL WRF SEEM TO INDICATE THE BEST CHANCES OF RAIN TODAY WILL BE IN THE EAST AND HAVE LEANED MORE TOWARD THE ECMWF WITH HIGHER RAIN CHANCES IN THIS REGION. HIGHS TODAY ARE EXPECTED TO BE IN THE LOWER 90S BUT WITH HUMIDITY...HEAT INDICES WILL NEAR 100 DEGREES. THROUGH WEDNESDAY NIGHT...THE UPPER TROUGH WILL CONTINUE TO PUSH OFF TO THE EAST AND UPPER RIDGING WILL MOVE INTO THE REGION FOR A WHILE. THERE COULD BE SOME SMALL RAIN CHANCES IN THE FAR SOUTH ON WEDNESDAY BUT IT APPEARS THAT MOST OF THE ARKLAMISS SHOULD BE DRY AS HEIGHTS WILL CONTINUE TO BUILD. TEMPERATURES ON WEDNESDAY WILL BE A TAD WARMER AND COULD FLIRT WITH THE 95-97 DEGREE RANGE. WEDNESDAY WILL BE A BIT MORE MUGGY AS THE COMBINATION OF HEAT AND 70 DEGREE DEWPOINTS WILL BRING HEAT INDICES NEAR 105 DEGREES. WILL CONTINUE WITH THE LIMITED RISK CURRENTLY ADVERTISED IN THE HWO AND GRAPHICS FOR HEAT INDICES DURING THIS TIME PERIOD. OVERNIGHT LOWS WILL DROP LOW ENOUGH TO PRECLUDE ANY NEED FOR AN ADVISORY. /28/ LONG TERM...THURSDAY THROUGH MONDAY...HOTTER AND DRIER THROUGH THE PERIOD. THURSDAY MORNING A LARGE 593DAM HIGH ATOP A 1019MB SURFACE HIGH WILL BE CENTERED JUST SOUTHEAST OF OUR CWA. THE SURFACE HIGH WILL BECOME CENTERED JUST SOUTH OF OUR CWA WHILE THE LARGE MID LEVEL HIGH STRENGTHENS AND BECOMES CENTERED OVER OUR CWA BY THURSDAY EVENING. A RATHER MOIST AIRMASS WILL BE IN PLACE WITH PWS OF 1.7-1.8 INCHES AND SURFACE DEW POINTS IN THE LOWER 70S. THE NORMAL AFTERNOON HIGHS ARE AROUND 92F AND TEMPERATURES WILL TOP OUT THURSDAY ABOVE NORMAL AT 95-97F AT MOST SITES. MODEL SOUNDINGS SUGGEST DRIER AIR WILL MIX DOWN DURING THE AFTERNOON LOWERING DEW POINTS IN THE UPPER 60S. THIS WILL KNOCK THE HUMIDITY DOWN SOME BUT THE HEAT AND HUMIDITY WILL COMBINE FOR MAXIMUM HEAT INDEX VALUES OF 100-103 THURSDAY. ISOLATED AFTERNOON STORMS WILL BE POSSIBLE IN THE SOUTHWEST THURSDAY BUT RAIN CHANCES WILL REMAIN VERY LOW ELSEWHERE THROUGH THE END OF THE WEEK. MODEL CONSENSUS IS A LITTLE SLOWER IN BREAKING DOWN THE LARGE RIDGE OVER OUR AREA UNTIL IT BEGINS SHIFTING EAST MONDAY. AS A RESULT HEAT AND HUMIDITY WILL REMAIN A CONCERN THROUGH THE WEEKEND INTO MONDAY. ABOVE NORMAL TEMPERATURES TOPPING OUT IN THE UPPER 90S EACH DAY WILL COMBINE WITH HIGH HUMIDITY TO RESULT IN HEAT INDEX VALUES PEAKING AROUND 105 FOR SEVERAL HOURS EACH AFTERNOON. A HEAT ADVISORY MAY BE NEEDED BY THE END OF THE WEEK IF GREATER HUMIDITY CAN BE MAINTAINED INTO THE AFTERNOON HOURS. AS THE MID LEVEL RIDGE SHIFTS EAST MONDAY OUR SOUTHERN ZONES WILL SEE A SLIGHT CHANCE OF STORMS BY AFTERNOON AND EVENING DUE ALSO IN PART TO THE SEA BREEZE FRONT PUSHING INTO THE AREA. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 94 73 96 73 / 36 14 7 6 MERIDIAN 92 71 96 72 / 42 12 10 5 VICKSBURG 94 71 96 71 / 20 11 4 7 HATTIESBURG 95 74 97 74 / 44 14 25 9 NATCHEZ 93 73 94 73 / 25 11 14 10 GREENVILLE 94 74 96 74 / 21 9 3 6 GREENWOOD 94 73 97 73 / 29 10 4 5 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ALLEN/19/28/22
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
651 AM EDT TUE AUG 19 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF A WEAK FRONT WHICH WILL APPROACH THIS AFTERNOON AND EVENING. THE FRONT WILL STALL ALONG THE OHIO VALLEY WEDNESDAY...THEN GRADUALLY LIFT NORTHEAST THROUGH THE END OF THE WEEK. DISTURBANCES TRACKING ALONG THE FRONT WILL KEEP THE WEATHER UNSETTLED THROUGH AT LEAST FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO INCLUDE A DENSE FOG ADVISORY ACROSS THE SOUTHERN HALF OF THE AREA WHERE THERE ARE QUITE A FEW OBSERVATIONS OF A QUARTER MILE OR LESS. LIGHT FOG WILL EXIST ELSEWHERE. PREVIOUS DISCUSSION... FAIRLY WEAK FLOW PATTERN OVER THE EASTERN CONUS TODAY AS A MID/UPPER LEVEL TROUGH DIGS INTO THE WESTERN GREAT LAKES. A WEAK SURFACE BOUNDARY ALONG THE OHIO RIVER WILL LIFT NORTH IN RESPONSE TO LOW PRESSURE ATTENDANT TO THE MID AND UPPER LEVEL FEATURE. A FEW RUNS OF THE RAP AND HRRR TRIED TO DEVELOP A FEW SHOWERS WITH THE BOUNDARY THIS MORNING...BUT HAVE KEPT THE FORECAST DRY BASED ON LATEST OBSERVATIONS. AS DAYTIME HEATING BUILDS...SOME CONVECTION MAY START DEVELOPING AROUND THE MIDDAY HOURS...BUT THIS WILL BE ISOLATED AT BEST. THE MAIN FOCUS WILL BE TO OUR WEST...AS SHOWERS AND STORMS FIRE ALONG A PREFRONTAL TROUGH. EXACT TIMING IS STILL IN QUESTION...BUT SOME STORMS COULD ARRIVE IN WEST CENTRAL OHIO BY LATE AFTERNOON. WILL DISCUSS THESE STORMS FURTHER IN THE SHORT TERM SECTION. BASED ON THE TEMPERATURE TRENDS FROM MONDAY...WE COULD WARM PRETTY NICELY WITH A LACK OF PRECIPITATION DURING PEAK HEATING. WENT A LITTLE ABOVE GUIDANCE FOR MOST... IN THE MID TO UPPER 80S AND INCREASING DEW POINTS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AN AREA OF SCATTERED TO NUMEROUS STORMS WILL BE CROSSING THE AREA DURING THE EVENING HOURS. MODERATE INSTABILITY...LIKELY BETWEEN 1-2K J/KG...WILL HAVE DEVELOPED DURING THE AFTERNOON. RICHER LOW LEVEL MOISTURE LOOKS LIKE IT WILL STAY TO THE SOUTHWEST OF OUR AREA. WHILE THERE IS SOME INCREASED MID LEVEL FLOW ASSOCIATED WITH THE DIGGING TROUGH...THE HIGHEST BULK SHEAR VALUES ARE GENERALLY TO OUR SOUTHWEST AS WELL. WITH THAT SAID...THERE ARE ENOUGH INGREDIENTS IN PLACE FOR AT LEAST SOME STRONGER STORMS...ESPECIALLY WEST OF I-75 WHERE SPC HAS HOISTED A SLIGHT RISK. A WEAKENING TREND IS EXPECTED THROUGH THE EVENING AS INSTABILITY IS LOST...BUT THE TIMING WILL BE IMPORTANT TO WHEN THIS OCCURS. INTERESTINGLY...THE LATEST MODEL RUNS ARE FOCUSING THE GREATEST COVERAGE NORTH OF THE OHIO RIVER...LIKELY CLOSEST TO THE STRONGER FORCING...SO ADJUSTED THE POPS ACCORDINGLY. THE NAM SEEMS A LITTLE TOO BULLISH IN DEVELOPING ADDITIONAL CONVECTION ALONG THE WEAK SURFACE FRONT. BASED ON DEEP LAYER MOISTURE...EXPECT A DRYING TREND TOWARD WEDNESDAY MORNING. MUGGY LOWS IN THE UPPER 60S TO AROUND 70. FORCING ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE PUSHING EAST ON WEDNESDAY...BUT THERE ARE SOME INDICATIONS THE SURFACE FRONT COULD REACTIVATE IN CENTRAL OHIO AROUND MIDDAY BEFORE PUSHING EAST. THE TAIL END OF THE FRONT WILL STALL ACROSS NORTHERN KENTUCKY...WARRANTING CHANCE POPS THERE AS WELL. HIGH TEMPERATURES IN THE MID 80S. FROM WEDNESDAY NIGHT THROUGH FRIDAY...MID AND UPPER LEVEL RIDGING WILL BEGIN BUILDING ACROSS THE CENTER OF THE COUNTRY AS TROUGHING DIGS INTO THE PACIFIC NORTHWEST. THIS WILL PLACE THE OHIO VALLEY UNDER INCREASING NORTHWEST FLOW WITH POTENTIAL FOR SOUTHEASTWARD DIVING DISTURBANCES. A NW-SE LOW LEVEL BAROCLINIC ZONE WILL TIGHTEN AS WELL WITH MOISTURE POOLED ALONG IT. THE CHANCE OF STORMS WILL INCREASE WEDNESDAY NIGHT IN THE TRI STATE AREA...OVERSPREADING THE REST OF THE REGION ON THURSDAY. FRIDAY WILL REMAIN UNSETTLED AS THE CORRIDOR OF FORCING MOVES ONLY SLIGHTLY NORTHEAST IN RESPONSE TO THE BUILDING RIDGE. EXPECT INCREASINGLY MUGGY CONDITIONS WITH HIGHS GENERALLY IN THE MID TO UPPER 80S AND LOWS ON EITHER SIDE OF 70. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... MID/UPPER LEVEL RIDGING OVER THE CENTRAL UNITED STATES WILL SHIFT SLOWLY EAST TOWARD THE LOWER OHIO VALLEY THROUGH THE WEEKEND. PCPN CHANCES SHOULD THEN BECOME MORE SUPPRESSED AS WE PROGRESS THROUGH THE WEEKEND AS THE RIDGE BUILDS IN FROM THE SOUTHWEST. SHORT WAVE ENERGY MOVING ACROSS THE GREAT LAKES WILL BEGIN TO WEAKEN THE RIDGE FROM THE NORTH LATE IN THE PERIOD...EVENTUALLY HELPING TO PUSH A COLD FRONT DOWN TOWARD OUR AREA. THIS MAY ALLOW FOR A CHANCE OF PCPN TOWARD THE END OF THE PERIOD ON MONDAY...BUT GIVEN THE MODEL DIFFERENCES WITH THE TIMING...WILL MAINTAIN A DRY FORECAST AT THIS POINT. TEMPERATURES WILL BE SOMEWHAT DEPENDENT ON THE TIMING AND DEGREE OF THUNDERSTORM ACTIVITY THROUGH LATE IN THE WEEK. HOWEVER...WITH THE HIGH BUILDING IN FROM THE SOUTHWEST...GENERALLY EXPECT A GRADUAL WARMING TREND TO ABOVE NORMAL HIGH TEMPERATURES THROUGH THE WEEKEND. OVERNIGHT LOWS WILL REMAIN ON THE WARM SIDE TOO WITH LOWS MOSTLY IN THE UPPER 60S TO AROUND 70 DEGREES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... FOG AND STRATUS ARE PREVALENT AT THE SOUTHERN TERMINALS OF KCVG...KLUK...AND KILN THIS MORNING. IFR/LIFR/VLIFR CONDITIONS SHOULD IMPROVE BETWEEN 14Z AND 17Z AS THE FOG AND STRATUS BURN OFF AND BECOME REPLACED BY BKN CUMULUS DECK. OTHERWISE...A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE WESTERN GREAT LAKES TODAY AND TONIGHT. FORECAST MODELS INDICATE THAT PERHAPS A PREFRONTAL TROF AXIS WILL TRAIL SOUTH FROM THIS LOW AND WILL PUSH EAST INTO OUR REGION LATE THIS AFTERNOON INTO THE EARLY MORNING HOURS OF WEDNESDAY. THIS TROF AXIS WILL THEN BE FOLLOWED BY A WEAK COLD FRONT LATE TONIGHT INTO WEDNESDAY MORNING. DAYTIME INSTABILITY AND ENOUGH SHEAR/CONVERGENCE WITH THE PREFRONTAL TROF AXIS SHOULD BRING AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS TO THE TERMINALS THIS EVENING INTO THE EARLY MORNING HOURS OF WEDNESDAY. HAVE PLACED VCTS/CB DESCRIPTORS AT THE SITES WHEN THIS IS MOST LIKELY TO OCCUR...BETWEEN 00Z AND 09Z. THE WEAK COLD FRONT WILL FOLLOW BEHIND THE TROF LATE TONIGHT...BUT IT APPEARS CONVERGENCE WILL BE WEAKER AND INSTABILITY WILL HAVE WANED SOME...SO COVERAGE APPEARS LESS WITH THIS BOUNDARY. OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR OHZ070>073- 077>082-088. KY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ089>100. IN...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1128 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... LOW CLOUDS SLOWLY LIFTING AND MOVING TO THE EAST. RADAR HAS DETECTED SHOWERS WHICH DEVELOPED ON THE WESTERN EDGE OF THIS CLOUD SHIELD AND HAS MOVED INTO CLEARFIELD COUNTY. SOME HINTS OF WEAK CONVECTION IN THE HRRR AND 4KM NAM. USED THESE MODELS TO ADD TEXTURE TO THE FORECAST SHOWING SHOWERS AND ISOLATED THUNDERSTORMS DRIFTING ACROSS PENNSYLVANIA THIS MORNING AND AFTERNOON. TRIED TO KEEP POPS IN CHANCE RANGE AS THERE IS LIMITED ORGANIZATION TO THE CONVECTION. HOWEVER...3KM HRRR UPDATES FROM NCEPS EXPERIMENTAL HRRR SHOW DIFFERENT AREAS OF SHOWERS IN CENTRAL PA ALL AFTERNOON AND NOW IMPLY MORE ORGANIZED THUNDERSTORMS IN S-SE COUNTIES IN LATE AFTERNOON EVENING. SEE HOW THIS EVOLVES. SKIES SHOULD SLOWLY GET BETTER DURING DAY CENTRAL AREAS. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... STILL LINGERING AREAS OF MVFR AND ISOLATED IFR AS THE LOW CLOUDS AND PATCHY FOG FROM EARLY THIS MORNING AND LIFT AND SLOWLY DRIFT TO THE EAST. A LINE OF SHOWERS WITH ISOLATED THUNDER HAS DEVELOPED OVER THE CENTRAL MOUNTAINS. THIS COULD BRING SHOWERS FROM KFIG SOUTH TO KAOO AND KJST AND EVENTUALLY THE KUNV AREA. ADDED SHOWERS VICINITY TO THESE SITES. THIS COULD MOVE FARTHER EAST. MODELS SHOW ISOLATED TO SCATTERED SHOWERS RANDOMLY PLACED ABOUT CENTRAL AND SOUTHERN PA OVER NEXT 12 HOURS. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS. RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID-LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... TUE...MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED...MORNING FOG/LOW CLOUDS SHRA/TSRA LIKELY WEST CHANCE EAST. THU-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1114 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... LOW CLOUDS SLOWLY LIFTING AND MOVING TO THE EAST. RADAR HAS DETECTED SHOWERS WHICH DEVELOPED ON THE WESTERN EDGE OF THIS CLOUD SHIELD AND HAS MOVED INTO CLEARFIELD COUNTY. SOME HINTS OF WEAK CONVECTION IN THE HRRR AND 4KM NAM. USED THESE MODELS TO ADD TEXTURE TO THE FORECAST SHOWING SHOWERS AND ISOLATED THUNDERSTORMS DRIFTING ACROSS PENNSYLVANIA THIS MORNING AND AFTERNOON. TRIED TO KEEP POPS IN CHANCE RANGE AS THERE IS LIMITED ORGANIZATION TO THE CONVECTION. HOWEVER...3KM HRRR UPDATES FROM NCEPS EXPERIMENTAL HRRR SHOW DIFFERENT AREAS OF SHOWERS IN CENTRAL PA ALL AFTERNOON AND NOW IMPLY MORE ORGANIZED THUNDERSTORMS IN S-SE COUNTIES IN LATE AFTERNOON EVENING. SEE HOW THIS EVOLVES. SKIES SHOULD SLOWLY GET BETTER DURING DAY CENTRAL AREAS. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL GIVE WAY TO FOG AND LOWERING VSBYS OVERNIGHT UNDER CLEAR SKIES AND LIGHT WINDS. EXPECT WIDESPREAD MVFR TO IFR VSBYS AND CIGS TO DEVELOP OVERNIGHT AT MOST CENTRAL AND NORTHERN AIRFIELDS. HOWEVER...HAVE NOT INCLUDED FOG IN THE LOWER SUSQUEHANNA TAFS OF KMDT AND KLNS...AS CONFIDENCE OF FORMATION IS LOWER. IF FOG DOES DEVELOP...LIKELY TO BE IN THE MVFR RANGE AT THESE LOCATIONS. CURRENT TIMING OF FOG IS FOR DEVELOPMENT AROUND 07Z IN MOST LOCATIONS...WITH THE DENSEST FOG BETWEEN 09Z AND 12Z. AFTER MORNING FOG...EXPECT GENERALLY VFR CONDITIONS. THERE IS A THREAT FOR SHRA/TSRA...MOST LIKELY IN THE SOUTHWEST AND LEAST LIKELY IN THE NORTHEAST. A VERY SLOW APPROACHING UPPER LOW WILL SLOWLY INCREASE CHANCES FOR DAILY SHOWERS AND POTENTIAL AFTERNOON TSRA FOR THE BALANCE OF THE WEEK. CURRENTLY...LATER WEDNESDAY AND THURSDAY LOOK LIKE THE HIGHEST LIKELIHOOD OF PRECIPITATION...WITH SURFACE FRONT CROSSING THE REGION. OUTLOOK... TUE...MORNING FOG...THEN MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD AVIATION...GRUMM/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
756 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... WEAK UPPER-LEVEL LOWS ARE STRUGGLING TO MAKE IT UNDER THE RETROGRADING UPPER LEVEL RIDGE. MODELS FOR DAYS NOW HAVE BEEN WETTER THAN REALITY. THE SREF AND GEFS ARE MORE ROBUST WITH SHOWER POTENTIAL TODAY THAN THE HIGH RESOLUTION CONVECTIVE FOLLOWING MODELS. LATEST 4KM NAM AND 3KM HRRR IMPLY SOME VERY ISOLATED CONVECTION ABOUT CENTRAL PA THIS AFTERNOON AND EARLY EVENING. NOTHING ORGANIZED OR SIGNIFICANT. SORT OF A QUANDARY HOW TO EFFECTIVELY USE THESE DATA VERSE THE LARGER SCALE MODELS WHERE CONVECTION IS GENERATED BY RELEASING INSTABILITY IN THE CONVECTIVE PARAMETERIZATION SCHEMES (CPS). BIASED POPS LOWER TOWARD CONVECTIVE ALLOWING MODELS THAT DO NOT USE CPS. MODELS IMPLY PARTLY TO MOSTLY CLOUDY TODAY. FIRST BATCH OF LOW CLOUDS IN SW PA WILL SHRINK AS IT ADVECTS ACROSS THE STATE. TEMPERATURE WISE CLOSE TO NORMAL. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... ANY SHOWER ACTIVITY THAT DEVELOPS SHOULD FADE FAST AROUND SUNSET. BUILDING 5940M RIDGE IN SOUTHERN US AND BLOCKING RIDGE TO OUR NORTH. WE ARE STUCK IN THE SQUEEZE PLAY BETWEEN THEM. AN ANEMIC FRONTAL SYSTEM TRIES TO PUSH THROUGH THE REGION. SREF LARGER SCALE MODELS SHOW SOME SURGE OF SLIGHTLY ABOVE NORMAL PW AND SOME CAPE INTO WESTERN PA. POPS SHOULD DROP OFF TO EAST AS THIS SYSTEM WILL WEAKEN AS IT MOVES BENEATH THE BLOCK. BEST CHANCE...AS MENTIONED BELOW FOR SEVERAL TENTHS WOULD BE IN WEST VERY LIGHT RAINFALL IN EASTERN AREAS. PREVIOUS: PASSAGE OF SHORTWAVE AND COOLING OF BLYR SHOULD CAUSE ANY EARLY EVENING SHOWERS TO DIMINISH SHORTLY AFTER SUNSET. HOWEVER...APPROACH OF UPPER LOW AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS COULD SPREAD SHRA/TSRA INTO THE NW MTNS TOWARD DAWN WED. HAVE RAISED POPS MARKEDLY ACROSS THE AREA WED...AS MDLS NOW IN AGREEMENT WITH TIMING OF LL JET/PLUME OF ANOMALOUS PWATS. BLEND OF OPER AND ENSEMBLE GUIDANCE SUGGESTS MOST LIKELY RAINFALL WED WILL RANGE FROM LESS THAN 0.10 INCHES SE OF HARRISBURG...TO ARND A HALF INCH ACROSS WARREN CO. HOWEVER...MUCH HIGHER LOCALIZED AMTS ARE LIKELY ACROSS THE W MTNS...WHERE ENVIRONMENT OF MODERATE INSTABILITY AND HIGH PWATS WILL MAKE LOCALLY HVY TSRA POSSIBLE. CONVECTION- ALLOWING MDLS SUPPORT THIS SCENARIO WITH SPOT AMTS OF ARND 2 INCHES ON WED ACROSS THE W MTNS. A MORE STABLE MARITIME AIR MASS OVR EASTERN PA WILL MAKE TSRA UNLIKELY THERE. GEFS 925 TEMPS ARE SUPPORTIVE OF HIGH TEMPS WED FROM THE M70S OVR THE ALLEGHENY PLATEAU...TO THE L80S OVR THE SUSQ VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL GIVE WAY TO FOG AND LOWERING VSBYS OVERNIGHT UNDER CLEAR SKIES AND LIGHT WINDS. EXPECT WIDESPREAD MVFR TO IFR VSBYS AND CIGS TO DEVELOP OVERNIGHT AT MOST CENTRAL AND NORTHERN AIRFIELDS. HOWEVER...HAVE NOT INCLUDED FOG IN THE LOWER SUSQUEHANNA TAFS OF KMDT AND KLNS...AS CONFIDENCE OF FORMATION IS LOWER. IF FOG DOES DEVELOP...LIKELY TO BE IN THE MVFR RANGE AT THESE LOCATIONS. CURRENT TIMING OF FOG IS FOR DEVELOPMENT AROUND 07Z IN MOST LOCATIONS...WITH THE DENSEST FOG BETWEEN 09Z AND 12Z. AFTER MORNING FOG...EXPECT GENERALLY VFR CONDITIONS. THERE IS A THREAT FOR SHRA/TSRA...MOST LIKELY IN THE SOUTHWEST AND LEAST LIKELY IN THE NORTHEAST. A VERY SLOW APPROACHING UPPER LOW WILL SLOWLY INCREASE CHANCES FOR DAILY SHOWERS AND POTENTIAL AFTERNOON TSRA FOR THE BALANCE OF THE WEEK. CURRENTLY...LATER WEDNESDAY AND THURSDAY LOOK LIKE THE HIGHEST LIKELIHOOD OF PRECIPITATION...WITH SURFACE FRONT CROSSING THE REGION. OUTLOOK... TUE...MORNING FOG...THEN MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM/FITZGERALD LONG TERM...FITZGERALD AVIATION...JUNG/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
747 AM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... WEAK UPPER-LEVEL LOWS ARE STRUGGLING TO MAKE IT UNDER THE RETROGRADING UPPER LEVEL RIDGE. MODELS FOR DAYS NOW HAVE BEEN WETTER THAN REALITY. THE SREF AND GEFS ARE MORE ROBUST WITH SHOWER POTENTIAL TODAY THAN THE HIGH RESOLUTION CONVECTIVE FOLLOWING MODELS. LATEST 4KM NAM AND 3KM HRRR IMPLY SOME VERY ISOLATED CONVECTION ABOUT CENTRAL PA THIS AFTERNOON AND EARLY EVENING. NOTHING ORGANIZED OR SIGNIFICANT. SORT OF A QUANDARY HOW TO EFFECTIVELY USE THESE DATA VERSE THE LARGER SCALE MODELS WHERE CONVECTION IS GENERATED BY RELEASING INSTABILITY IN THE CONVECTIVE PARAMETERIZATION SCHEMES (CPS). BIASED POPS LOWER TOWARD CONVECTIVE ALLOWING MODELS THAT DO NOT USE CPS. MODELS IMPLY PARTLY TO MOSTLY CLOUDY TODAY. FIRST BATCH OF LOW CLOUDS IN SW PA WILL SHRINK AS IT ADVECTS ACROSS THE STATE. TEMPERATURE WISE CLOSE TO NORMAL. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... ANY SHOWER ACTIVITY THAT DEVELOPS SHOULD FADE FAST AROUND SUNSET. BUILDING 5940M RIDGE IN SOUTHERN US AND BLOCKING RIDGE TO OUR NORTH. WE ARE STUCK IN THE SQUEEZE PLAY BETWEEN THEM. AN ANEMIC FRONTAL SYSTEM TRIES TO PUSH THROUGH THE REGION. SREF LARGER SCALE MODELS SHOW SOME SURGE OF SLIGHTLY ABOVE NORMAL PW AND SOME CAPE INTO WESTERN PA. POPS SHOULD DROP OFF TO EAST AS THIS SYSTEM WILL WEAKEN AS IT MOVES BENEATH THE BLOCK. BEST CHANCE...AS MENTIONED BELOW FOR SEVERAL TENTHS WOULD BE IN WEST VERY LIGHT RAINFALL IN EASTERN AREAS. PREVIOUS: PASSAGE OF SHORTWAVE AND COOLING OF BLYR SHOULD CAUSE ANY EARLY EVENING SHOWERS TO DIMINISH SHORTLY AFTER SUNSET. HOWEVER...APPROACH OF UPPER LOW AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS COULD SPREAD SHRA/TSRA INTO THE NW MTNS TOWARD DAWN WED. HAVE RAISED POPS MARKEDLY ACROSS THE AREA WED...AS MDLS NOW IN AGREEMENT WITH TIMING OF LL JET/PLUME OF ANOMALOUS PWATS. BLEND OF OPER AND ENSEMBLE GUIDANCE SUGGESTS MOST LIKELY RAINFALL WED WILL RANGE FROM LESS THAN 0.10 INCHES SE OF HARRISBURG...TO ARND A HALF INCH ACROSS WARREN CO. HOWEVER...MUCH HIGHER LOCALIZED AMTS ARE LIKELY ACROSS THE W MTNS...WHERE ENVIRONMENT OF MODERATE INSTABILITY AND HIGH PWATS WILL MAKE LOCALLY HVY TSRA POSSIBLE. CONVECTION- ALLOWING MDLS SUPPORT THIS SCENARIO WITH SPOT AMTS OF ARND 2 INCHES ON WED ACROSS THE W MTNS. A MORE STABLE MARITIME AIR MASS OVR EASTERN PA WILL MAKE TSRA UNLIKELY THERE. GEFS 925 TEMPS ARE SUPPORTIVE OF HIGH TEMPS WED FROM THE M70S OVR THE ALLEGHENY PLATEAU...TO THE L80S OVR THE SUSQ VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL GIVE WAY TO FOG AND LOWERING VSBYS OVERNIGHT UNDER CLEAR SKIES AND LIGHT WINDS. EXPECT WIDESPREAD MVFR TO IFR VSBYS AND CIGS TO DEVELOP OVERNIGHT AT MOST CENTRAL AND NORTHERN AIRFIELDS. HOWEVER...HAVE NOT INCLUDED FOG IN THE LOWER SUSQUEHANNA TAFS OF KMDT AND KLNS...AS CONFIDENCE OF FORMATION IS LOWER. IF FOG DOES DEVELOP...LIKELY TO BE IN THE MVFR RANGE AT THESE LOCATIONS. CURRENT TIMING OF FOG IS FOR DEVELOPMENT AROUND 07Z IN MOST LOCATIONS...WITH THE DENSEST FOG BETWEEN 09Z AND 12Z. AFTER MORNING FOG...EXPECT GENERALLY VFR CONDITIONS. THERE IS A THREAT FOR SHRA/TSRA...MOST LIKELY IN THE SOUTHWEST AND LEAST LIKELY IN THE NORTHEAST. A VERY SLOW APPROACHING UPPER LOW WILL SLOWLY INCREASE CHANCES FOR DAILY SHOWERS AND POTENTIAL AFTERNOON TSRA FOR THE BALANCE OF THE WEEK. CURRENTLY...LATER WEDNESDAY AND THURSDAY LOOK LIKE THE HIGHEST LIKELIHOOD OF PRECIPITATION...WITH SURFACE FRONT CROSSING THE REGION. OUTLOOK... TUE...MORNING FOG...THEN MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM/FITZGERALD LONG TERM...FITZGERALD AVIATION...JUNG/GARTNER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
320 PM MDT TUE AUG 19 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 249 PM MDT TUE AUG 19 2014 WV SATELLITE IMAGERY TODAY SHOWING THE MONSOON MSTR PLUME OVR UT...BUT SLOWLY SHIFTING EASTWARD AS AN UPR LOW MOVES SOUTHWARD ALONG THE CA COAST. SCATTERED SHOWERS AND TSTMS ARE EXPECTED THIS EVENING OVR THE MTNS AND UPR ARKANSAS RIVER VALLEYS...WITH ISOLD ACTIVITY OVR THE SERN PLAINS. BY 03Z THE HRRR AND RAP SHOW LITTLE IF ANY PCPN OVR THE SERN PLAINS...WITH JUST SOME ISOLD PCPN OVR THE MTN AREAS. OVERNIGHT THAT UPR LOW WL MOVE OVR SRN CA AND THE MONSOON PLUME SHIFTS INTO WRN CO. AS A WX DISTURBANCE THE MSTR LIFTS NORTHEASTWARD ACRS NWRN CO...SOME PCPN WL PROBABLY CONTINUE THRU THE NIGHT ALONG THE CONTDVD...ESPECIALLY OVR THE CENTRAL CO MTNS WHICH WL BE CLOSEST TO THE DISTURBANCE AND BETTER MSTR. ON WED THE UPR LOW IS EXPECTED TO REMAIN OVR SRN CA. THE BEST MSTR GOES NORTH OF THE AREA WITH THAT DISTURBANCE...AND MODELS ARE MAINLY SHOWING SPOTTY PCPN FOR THE FORECAST AREA. WILL KEEP SCT POPS OVR THE MTNS AREAS FOR WED AFTERNOON AND ISOLD POPS OVR THE SAN LUIS VALLEY AND I-25 CORRIDOR. HIGH TEMPS ON WED SHOULD GENERALLY BE AROUND TO A LITTLE ABOVE AVERAGE. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 249 PM MDT TUE AUG 19 2014 THE UPPER LEVEL PATTERN IS FORECAST TO FEATURE A BROAD UPPER LEVEL TROUGH OVER THE NORTHWEST TO NORTH-CENTRAL CONUS AND A HIGH PRESSURE CENTER OVER THE SOUTHEAST STATES. THIS WILL PUT SOUTHERN COLORADO UNDER SOUTHWESTERLY FLOW FOR MUCH OF THE EXTENDED. THERE ARE MODEL DIFFERENCES IN HOW THEY WANT TO HANDLE UPPER LEVEL DISTURBANCES IN THE FLOW...AND ENSEMBLES DEVELOP HIGH SPREADS BY THIS WEEKEND LEADING TO LOWER CONFIDENCE IN THE LAST COUPLE OF DAYS OF THE EXTENDED PERIOD. THE GFS HAS REMAINED CONSISTENT FROM RUN TO RUN WITH AN UPPER LEVEL LOW OVER SOUTHERN CALIFORNIA AND EJECTING IT NORTHEAST ACROSS COLORADO ON THURSDAY NIGHT INTO FRIDAY. THE LATEST ECMWF IS MORE IN LINE WITH THIS SOLUTION...HOWEVER IS ABOUT 24 HOURS SLOWER IN EJECTING THE SYSTEM OUT. THE BIGGEST FORECAST CHANGE FOR THE GFS IS WHERE THE SYSTEM DEVELOPS CONVECTION ON THURSDAY. EXPECT ONGOING CONVECTION ACROSS THE MOUNTAINS WEDNESDAY EVENING WITH MODELS BRINGING BAND EAST ACROSS THE PLAINS THROUGH THE OVERNIGHT HOURS AS A WEAK DISTURBANCE LIFTS NORTHEAST. BY THURSDAY MORNING...THE LOW PRESSURE CENTER OVER SOUTHERN CALIFORNIA IS FORECAST TO OPEN UP AND LIFT NORTHEAST ACROSS COLORADO. THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE MOUNTAINS BY LATE THURSDAY MORNING. THUNDERSTORMS DEVELOPMENT IS THEN EXPECTED EASTWARD ACROSS THE PALMER DIVIDE THROUGH THE AFTERNOON AND EVENING HOURS. THE PREVIOUS RUN OF THE GFS HAD THIS THUNDERSTORM DEVELOPMENT FURTHER SOUTH OVER SOUTHERN COLORADO...SO WHERE THIS DISTURBANCE EJECTS WILL PLAY A ROLE IN WHAT AREAS SEEN THE POTENTIAL FOR HEAVIER PRECIPITATION. THE ECMWF AND NAM SOLUTIONS ARE A BIT SLOWER WITH THIS SYSTEM...WITH IT EJECTING ACROSS SOUTHERN COLORADO ON FRIDAY AFTERNOON. IF THIS IS THE CASE...THURSDAYS CONVECTION WILL LIKELY REMAIN TIED TO THE TERRAIN AND PALMER DIVIDE...WITH NOT MUCH EXPECTED ON THE PLAINS. THE HEAVY PRECIPITATION CHANCES WOULD THEN FOCUS ON FRIDAY AFTERNOON AND NIGHT...WITH HEAVY RAINFALL AND THE POTENTIAL FOR FLASH FLOODING. THE IMPORTANT THING TO REMEMBER...IS THAT SOME TIME BETWEEN THURSDAY AND FRIDAY NIGHT...SOUTHERN COLORADO WILL LIKELY SEE A PERIOD OF WIDESPREAD HEAVIER RAINFALL. A BROAD TOUGH IS FORECAST TO REMAIN ENTRENCHED ACROSS THE PACIFIC NORTHWEST INTO THE NORTHERN PLAINS SATURDAY THROUGH TUESDAY. THE MAIN FORECAST ISSUE WILL BE HOW DEEP THE TROUGH GETS. THE GFS SOLUTIONS DIGS IT THE FURTHEST SOUTH...WITH CONTINUED ACTIVE WEATHER ACROSS THE AREA...WHILE THE ECMWF IS KEEP MOST OF THE ENERGY CONFINED TO OUR NORTH WITH LESS CHANCES FOR PRECIPITATION. A COLD FRONT IS FORECAST TO DROP SOUTH ACROSS THE PLAINS ON SUNDAY WHICH MAY BE THE BEST OPPORTUNITY FOR WIDESPREAD PRECIPITATION ACROSS THE AREA. OTHERWISE...CONVECTION WILL LIKELY REMAIN OVER THE MOUNTAINS WITH LIMITED ACTIVITY OVER THE PLAINS. MOZLEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 249 PM MDT TUE AUG 19 2014 VFR CONDITIONS ARE EXPECTED THIS EVENING THROUGH WEDNESDAY AFTERNOON AT KCOS...KPUB AND KALS. SOME TSTMS MAY MOVE INTO THE VCNTY OF THE TERMINAL SITES THIS EVENING...AND THEN AGAIN ON WED AFTERNOON. THE MAIN THREATS WITH TSTMS WILL BE GUSTY WINDS AND LIGHTNING...BUT SOME LOCALLY HEAVY RAIN IS ALSO POSSIBLE. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...MOZLEY AVIATION...28
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
125 PM CDT TUE AUG 19 2014 .DISCUSSION... 1114 AM CDT MAIN CONCERNS/CHALLENGES FOR MORNING UPDATE WERE MONITORING SHOWER/THUNDERSTORM CHANCES THIS MORNING THROUGH THE AFTERNOON. LATEST RADAR IMAGERY SHOWING THUNDERSTORM COMPLEX WHICH HAS MOVED THROUGH NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS THIS MORNING...CONTINUING EAST AND CURRENTLY IMPACTING AREAS FROM LA SALLE TO PONTIAC. EXPECT THIS COMPLEX TO CONTINUE EAST THROUGH THE EARLY AFTERNOON...WITH THUNDERSTORMS LIKELY TO BUILD FURTHER TO THE NORTHEAST TOWARDS THE CHICAGO METRO AREA OVER THE ONE TO TWO HOURS...ALONG APPROACHING SURFACE TROUGH AND FRONT TO THE NORTHWEST. FEEL FAIRLY CONFIDENT WITH THIS POSSIBILITY AS THIS MID LEVEL WAVE AND SURFACE TROUGH/FRONT WILL MOVE THROUGH AN ENVIRONMENT WITH LITTLE TO NO CIN AND MODERATE INSTABILITY. CONFIDENCE IS LOWER WITH REGARD TO INTENSITY OF THESE STORMS AS LARGE CLOUD SHIELD HAS LIMITED STEEPNESS OF LOW LEVEL LAPSE RATES...AND WITH WESTERLIES/BULK SHEAR VALUES REMAINING ON THE LOWER SIDE. COULD SEE THE STRONGEST DEVELOPMENT OCCURRING OVER EAST CENTRAL ILLINOIS AND NORTHWEST INDIANA AS THIS BROKEN LINE OF THUNDERSTORMS PUSHES EAST/SOUTHEAST THROUGH MID AFTERNOON...WITH AN ISOLATED SEVERE THREAT STILL POSSIBLE. HIGH WIND GUSTS WOULD BE THE MAIN THREAT...AS WELL AS HEAVY RAINFALL. SURFACE DEWPOINTS RIGHT AROUND 70 DEG WITH AXIS OF HIGHEST PWATS RIGHT OVER THE SOUTHEAST TWO THIRDS OF THE CWA SHOULD ALLOW FOR EFFICIENT RAIN PRODUCERS TODAY...AND HAVE MADE MENTION OF THIS POTENTIAL FOR LOCALLY HEAVY RAINFALL IN THE HWO. RODRIGUEZ //PREV DISCUSSION... 336 AM CDT SHORT TERM...THROUGH TUESDAY NIGHT... FOR THE REMAINDER OF THE OVERNIGHT HOURS...THE MAIN FOCUS WILL BE THE PROGRESSION OF THUNDERSTORMS ALONG A WEAK COLD FRONT MOVING THROUGH SRN WI/NERN IA AND PUSHING INTO NRN IL. THE MAIN SHORTWAVE ASSOCIATED WITH THE ACTIVITY IS MOVING QUICKLY OVER ERN WI AND CNTRL LAKE MICHIGAN. AS THE SHORTWAVE RACES RATHER QUICKLY TO THE EAST...THE LINE OF THUNDERSTORMS IS TAKING ON A MORE EAST-WEST ORIENTATION ALONG THE WISCONSIN BORDER...BUT IS SAGGING INTO WINNEBAGO AND BOONE COUNTIES. SOME STRONG THUNDERSTORMS ALONG THIS PORTION OF THE FRONT HAVE THE POTENTIAL TO PRODUCE SOME SMALL HAIL AND LOCALIZED STRONGER WIND GUSTS. THERE IS STILL SOME CONCERN ABOUT HOW FAR SOUTH THE ACTIVITY WILL REACH. CURRENTLY ANTICIPATE THAT THE GREATEST THUNDERSTORM COVERAGE SHOULD BE OVER THE NORTHERN TIER COUNTIES ALONG THE WISCONSIN BORDER. HOWEVER...THERE IS STILL SOME SWLY FLOW ALOFT WITH WITH 850MB WINDS ARND 30KT...WHILE SFC FLOW IS LIGHT AND GENERALLY SOUTHERLY. THERE IS PLENTY OF LOW LEVEL MOISTURE IN PLACE AND WITH AT LEAST MODEST ISENTROPIC LIFT IN THE WARM SECTOR WHICH COULD AT LEAST GENERATE SCT SHRA/TSRA. THE LATEST HIGH RES GUIDANCE IS INDICATING A DIMINISHING TREND TO THE CONVECTION ALONG THE SRN PORTION OF THE FRONT AS IT MOVES THROUGH THE AREA THIS MORNING...SO HAVE BACKED OFF POPS TO SLIGHT CHANCE...BUT WITH DAYTIME WARMING...THERE SHOULD BE AN UPTICK IN THE CONVECTIVE ACTIVITY AD THE FRONT PUSHES THROUGH THE SRN PORTIONS OF THE CHICAGO METRO AREA AND INTO ECNTRL IL AND NWRN INDIANA. PORTIONS OF THE CWA. WITH INCREASING SLWY DEVELOPING WITH THE APPROACH OF THE COLD FRONT AND VEERING TO WLY FOLLOWING THE FROPA...NO LAKE BREEZE DEVELOPMENT IS EXPECTED TODAY AND THE WARM AIR SHOULD HAVE NO TROUBLE REACHING RIGHT UP TO THE LAKEFRONT...WITH TEMPS IN THE LOWER TO MIDDLE 80S EXPECTED FOR THE ENTIRE CWA. ANY RESIDUAL PCPN ASSOCIATED WITH THE PASSING COLD FRONT SHOULD PUSH TO THE EAST OF THE CWA BY LATE THIS EVENING. WEAK HIGH PRESSURE SHOULD BUILD IN BEHIND THE FRONT WEDNESDAY EVENING AND OVERNIGHT. WITH GENERALLY WLY FLOW BEHIND THE FRONT...AND NO SGFNT DRY AIR UPSTREAM...THE LOW LEVELS SHOULD REMAIN VERY MOIST...SO FOG DEVELOPMENT LATE TUESDAY NIGHT AND POSSIBLY INTO WEDNESDAY MORNING IS A DISTINCT POSSIBILITY. KREIN WEDNESDAY THROUGH THURSDAY... MAIN FEATURE IN THE MEDIUM TERM WILL BE THE DEPARTING MID-LVL VORT FROM THE GREAT LAKES...STEADILY WEAKENING AND EJECTING EAST. MEANWHILE A DEVELOPING 500MB RIDGE WILL TAKE SHAPE ACROSS THE PLAINS...THEN LIFT NORTHEAST THUR. THE STALLED FRONTAL BOUNDARY WILL REMAIN SOUTH OF THE FORECAST AREA THRU WED THEN AS THE RIDGE STEADILY BUILDS AND EXPANDS NORTH WARM AIR ADVECTION WILL LIFT THE BOUNDARY NORTH. THIS WILL LIKELY FEATURE MOISTENING LLVLS WITH DECENT ISENTROPIC LIFT ALONG THE BOUNDARY...TO SUPPORT INCREASING POPS LATE WED FROM SOUTH TO NORTH. WHILE IT APPEARS FAVORABLE FOR A CHANNEL OF LIKELY POPS LATE WED-EARLY THUR...THERE IS SOME CONCERN THAT WE COULD QUICKLY BECOME CAPPED WITH A STRONG PUSH OF VERY WARM AIR ALOFT. SOME GUIDANCE IS SUGGESTING AFT 00Z 850MB THERMAL TEMPS RISE TO ARND 19-20 DEG C...WHICH COULD BE ENOUGH TO LIMIT COVERAGE/INTENSITY. HOWEVER IF THIS ENDS UP BEING SLIGHTLY COOLER ANY PRECIP THAT DOES DEVELOP COULD EASILY PRODUCE LOCALLY HEAVY RAINFALL...AS PWAT VALUES ARE EXPECTED TO RISE TO NEAR 1.7-2.0" OVERNIGHT. TEMPS WED WILL PUSH INTO THE MID 80S...HOWEVER IT IS PLAUSIBLE THAT A WEAK LK BREEZE COULD FORM EARLY IN THE AFTN AND KEEP THE NEARSHORE AREAS COOLER. WITH WARM AIR STEADILY ADVECTING NORTH INTO THE FORECAST AREA...EXPECT TEMPS TO REMAIN MILD OVERNIGHT IN THE MID/UPR 60S. IF CLOUDS AND PRECIP ARRIVE EARLIER WED EVE...THEN TEMPS MAY NOT DIP BELOW 70. THUR WILL FEATURE STEADILY RISING MID-LVL HEIGHTS AS THE ROBUST RIDGE ESTABLISHES ITSELF ACROSS A BULK OF OF THE REGION. THIS POSES CHALLENGES WITH PRECIP FOR THUR. GUIDANCE CONTINUES TO FAVOR A SHORTWAVE LIFTING NORTHEAST INTO THE UPPER MIDWEST WITH BETTER MID-LVL VORTICITY THEN SLIDING EAST ALONG THE NORTHERN PERIPHERY OF THE RIDGE...BEFORE DIVING SOUTHEAST TOWARDS THE EASTERN GREAT LAKES. THIS COUPLED WITH VERY WARM 850MB TEMPS NEARING 20 DEG C MAY RESULT IN A CAPPED ENVIRONMENT. CONFIDENCE IS NOT YET STRONG ENOUGH TO FURTHER REDUCE POPS THUR AFTN. DEPENDING ON CLOUDS/PRECIP THUR WILL STEER HOW WARM SFC TEMPS BECOME. GUIDANCE CONTINUES TO POINT TOWARDS MID/UPR 80S. DEW PTS WILL BE PUSHING INTO THE LOW 70S...WHICH THE COMBINATION OF TEMP/DEW PT COULD BE SUPPORTIVE OF HEAT INDEX VALUES NEARING THE MID 90S. CONCERN REMAINS FOR THUR NGT ON POPS...BUT MORE IMPORTANTLY ON POTENTIAL FOR HEAVY RAINFALL. PWAT VALUES CONTINUE TO HOVER ARND 2" WITH VERY WARM DEW PTS BETWEEN 72-74 DEG. WITH THE LACK OF A STRONG WIND FIELD...STORMS COULD BE SLOW MOVING AND EASILY PRODUCE LOCALLY HEAVY RAINFALL. OVERNIGHT LOWS MAY NOT DIP BELOW THE MID/UPR 70S...WHICH SETS THE STAGE FOR A POTENTIALLY HOT/HUMID DAY FRI. FRIDAY THROUGH EARLY NEXT WEEK... MID-LVL RIDGING CONTINUES TO BE PROGGED FOR THE FRI-SUN PERIODS...WHICH SETS THE STAGE FOR POTENTIALLY A VERY WARM STRETCH ACROSS THE REGION WITH NUMEROUS AREAS REACHING 90 DEG IN THIS TIMEFRAME. GUIDANCE CONTINUES TO FAVOR A HIGH PROBABILITY THAT DEW PTS WILL EASILY REMAIN IN THE 72-74 DEG RANGE FRI/SAT...WHICH COUPLED WITH TEMPS ARND 90 COULD EASILY PRODUCE 100 DEG HEAT INDEX READINGS. THE CURRENT ECMWF SOLUTION PAINTS AN EVEN WARMER THERMAL RIDGE AT 850MB FOR SUN AT 23-25 DEG C. CLOUDS/PRECIP WILL LIKELY STEER HOW WARM SUN BECOMES. THEN ENSEMBLES CONTINUE TO DEMONSTRATE SOME CONSISTENCY THAT THE MID-LVL RIDGE WILL WEAKEN EARLY NEXT WEEK WITH A RETURN TO TROUGHING ACROSS THE MIDDLE OF THE CONUS. CURRENT GUIDANCE SUGGESTS A FRONTAL BOUNDARY WILL ARRIVE IN THE MON/TUE TIMEFRAME AND BRING TEMPS BACK TO SEASONAL OR SLIGHTLY SUB-SEASONAL CONDS FOR THE MIDDLE OF NEXT WEEK. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * ISOL SHRA/TSRA POSSIBLE THROUGH MID AFTERNOON. * WESTERLY WINDS GUSTING TO AROUND 20 KT THROUGH EARLY EVENING. * POTENTIAL FOR MVFR VIS IN BR LATE TONIGHT INTO WED MORNING. RODRIGUEZ //DISCUSSION...UPDATED 18Z... LATEST RADAR IMAGERY SHOWING AREA OF THUNDERSTORMS EXITING TO THE EAST OF THE TERMINALS...BUT WITH GYY THE ONLY TERMINAL BEING IMPACTED AT THIS TIME. THIS WILL CONTINUE EAST OVER THE NEXT HOUR WITH GENERALLY DRY CONDITIONS THEN EXPECTED OVER THE NEXT SEVERAL HOURS. ISOL TO WIDELY SCATTERED SHOWERS ARE STILL DEVELOPING OVER FAR NORTHERN ILLINOIS AND SOUTHERN WISCONSIN...OUT AHEAD OF FRONT STRETCHED FROM SOUTHERN WISCONSIN TO EASTERN IOWA. THIS WILL LIKELY CONTINUE INTO THE AFTERNOON AS THIS FRONT DROPS TO THE SOUTHEAST...BUT EXPECT IT TO REMAIN LIMITED IN COVERAGE AS BETTER LIFT ALOFT IS LOST. ONLY HAVE VCSH MENTIONED DUE TO ANTICIPATED COVERAGE...BUT WILL NEED TO CONTINUE MONITORING THE POTENTIAL FOR A STRAY SHOWER AND EVEN AN OUTSIDE POSSIBILITY FOR A BRIEF/ISOL STORM TO MOVE OVER THE TERMINALS. CEILINGS STILL HOVERING AROUND MVFR/VFR...BUT WITH VFR CEILINGS EXPECTED THIS AFTERNOON THROUGH THE REST OF THE FORECAST PERIOD. FAIRLY MOIST CONDITIONS LINGERING TONIGHT COULD ALLOW FOR FOG DEVELOPMENT...AND HAVE CONTINUED MENTION OF THIS IN THE TAF. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM HIGH CONFIDENCE WITH ISOL SHRA/TSRA DEVELOPING AROUND THE TERMINALS THIS AFTERNOON...LOW CONFIDENCE WITH THIS IMPACTING THE TERMINALS. * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. * MEDIUM CONFIDENCE WITH MVFR VIS OCCURRING LATE TONIGHT INTO WEDNESDAY MORNING. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR TSRA AND OCNL REDUCED CIGS/VIS. SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL. && .MARINE... 316 AM CDT AN AREA OF LOW PRESSURE OVER CENTRAL WISC WILL CONTINUE TO DRIFT NORTHEAST ACROSS THE NORTHERN PORTION OF THE LAKE MIDDAY...THEN CONTINUE TO SLIDE EAST AND WEAKEN WEDNESDAY AFTERNOON ACROSS SOUTHEAST ONTARIO. THE GRADIENT IS EXPECTED TO TIGHTEN SLIGHTLY FROM THE SOUTH...WITH WINDS INCREASING THIS MORNING TO ARND 15 TO 25KT. THEN AS THE LOW SLIDES EAST WINDS WILL BECOME WEST AND DIMINISH TO ARND 10 TO 20 KT LATE TONIGHT. WAVES SHUD BE ABLE TO BRIEFLY BUILD ACROSS THE LAKE TO ARND 2-4FT...THEN WITH A LIGHTER GRADIENT ARRIVING WED WAVES WILL SUBSIDE TO ARND 2 FT OR LESS. IN THE DEPARTING SFC LOW WILL BE A MUCH WEAKER GRADIENT...WITH WINDS GENERALLY LIGHT FROM THE NORTH ARND 5 TO 10 KT ACROSS THE NORTHERN HALF OF THE LAKE AND AROUND 10 KT FROM THE SOUTH FOR THE SOUTHERN HALF OF THE LAKE. A WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE SOUTHERN PORTION OF THE LAKE EARLY THUR...WITH MUCH WARMER AIR LIFTING OVER THE LAKE. AT THIS TIME FEEL THAT FOG MAY NOT DEVELOP...BUT COULD SEE SOME HAZY CONDITIONS DEVELOP LATE IN THE WEEK. SOUTH/SOUTHEAST WINDS FOR THE WEEKEND. THE UPPER FLOW PATTERN DOES LOOK TO SHIFT SUNDAY OR MONDAY BRINGING A COLD FRONT ACROSS THE LAKE WITH A SHIFT TO NORTHERLY WINDS WHICH MAY BE RATHER BREEZY EARLY NEXT WEEK. BEACHLER && .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 1244 PM CDT Tue Aug 19 2014 .UPDATE... ISSUED AT 923 CDT TUE AUG 19 2014 Area of showers and thunderstorms associated with an upper-level wave is currently crossing the Mississippi River into west-central Illinois. 1417z radar imagery shows leading edge of precip extending from Galesburg...to Rushville...to Bowling Green Missouri. Based on timing tools, showers/thunder will arrive along the I-55 corridor by midday. HRRR and other high-res models generally show the precip area weakening as it pushes eastward through the morning, then potentially re-developing across east-central Illinois later this afternoon. Made some adjustments to hourly PoPs today, mainly to increase to categorical along/west of I-55 during the morning. Once the wave passes, rain chances will come to an end across the Illinois River Valley by mid to late afternoon, followed by a return to partly to mostly sunny skies. Further east, rain chances will linger throughout the day before coming to an end by evening. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 336 AM CDT TUE AUG 19 2014 Short term models have trended slower with the front and precip that is currently supposed to be moving into the area. But will still have chance of precip starting in the northwest parts of the cwa this morning. Then will progress the pcpn chances southeastward across the cwa during the day. By this evening, most of the pcpn will be in the eastern two thirds of the area with the highest pops in the southeast. By overnight, the pcpn should have moved southeast of the area so most of the area should be dry overnight, though will keep a slight chance of pops in the southeast after midnight. Could be some additional pcpn in the southwest late tonight, but models keep most of pcpn west of the area through 12z. Temps will begin the slow warming tomorrow, and am expecting mid to upper 80s throughout the area today. && .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 347 AM CDT TUE AUG 19 2014 Models still pretty consistent with the development and lift of a boundary through the Midwest on Wednesday. Boundary will have little reflection at the sfc with very weak flow/weak wind shift, and thermal gradient is better represented in the mid levels. Boundary will provide a weak focus for waves moving through the region as the boundary lifts to the NE through the area for Wed/Wed night. Though Wed is lacking signif pop for now, the timing of the progression is better for early evening and into the overnight on Wednesday night/shifting to the northeast for Thurs. Position of the boundary or the remnants thereof will be where the majority of the precip chances will be...increasing to the north, particularly north of Interstate 74 from Thursday to Saturday. Ample sfc based instability in the form of hot and humid conditions as the ridge over the southwest opens and spreads signif heat into the Midwest. Models have also shown consistency with 850 mb temps in the 19-25C range from Wednesday through Sunday. This will drive the temps into the upper 80s/lower 90s with heat indices in the upper 90s/approaching 100F. A far more summer-like pattern than much of the season so far, and well above normal for this time of year...with breaks from the heat provided by any thunderstorms that may have the chance to form from more diurnal instability with any frontal forcing further to the north. Into the extended, day 7/just into day 8, models diverge in solutions with major difference in breaking down the upper ridge for the Midwest. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) ISSUED AT 1244 PM CDT TUE AUG 19 2014 17z surface analysis shows cold front across eastern Iowa approaching the Mississippi River. Earlier convection that pushed into the Illinois River Valley ahead of the front continues to diminish as it tracks toward the I-57 corridor. Based on latest satellite/radar trends, it appears chances for additional convection at KPIA are slim to none, so have gone with a dry forecast there. Further southeast at the remaining terminals, will carry either VCTS or a TEMPO group for thunder this afternoon. Atmosphere has been temporarily stabilized due to clouds/showers this morning, but as skies partially clear, think scattered showers/storms will develop east of the Illinois River through the afternoon. Any convection that fires up will push into Indiana by early evening, followed by clearing skies tonight. Given clear skies and light winds, think areas of fog will once again develop. Have dropped visbys lowest at KPIA where quite a bit of rain fell earlier, but have gone with 2-3 miles everywhere between 07z and 14z. After that, mostly clear skies with a light W/SW wind will prevail by Wednesday morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...AUTEN LONG TERM...HJS AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1113 AM CDT TUE AUG 19 2014 .DISCUSSION... 336 AM CDT SHORT TERM...THROUGH TUESDAY NIGHT... FOR THE REMAINDER OF THE OVERNIGHT HOURS...THE MAIN FOCUS WILL BE THE PROGRESSION OF THUNDERSTORMS ALONG A WEAK COLD FRONT MOVING THROUGH SRN WI/NERN IA AND PUSHING INTO NRN IL. THE MAIN SHORTWAVE ASSOCIATED WITH THE ACTIVITY IS MOVING QUICKLY OVER ERN WI AND CNTRL LAKE MICHIGAN. AS THE SHORTWAVE RACES RATHER QUICKLY TO THE EAST...THE LINE OF THUNDERSTORMS IS TAKING ON A MORE EAST-WEST ORIENTATION ALONG THE WISCONSIN BORDER...BUT IS SAGGING INTO WINNEBAGO AND BOONE COUNTIES. SOME STRONG THUNDERSTORMS ALONG THIS PORTION OF THE FRONT HAVE THE POTENTIAL TO PRODUCE SOME SMALL HAIL AND LOCALIZED STRONGER WIND GUSTS. THERE IS STILL SOME CONCERN ABOUT HOW FAR SOUTH THE ACTIVITY WILL REACH. CURRENTLY ANTICIPATE THAT THE GREATEST THUNDERSTORM COVERAGE SHOULD BE OVER THE NORTHERN TIER COUNTIES ALONG THE WISCONSIN BORDER. HOWEVER...THERE IS STILL SOME SWLY FLOW ALOFT WITH WITH 850MB WINDS ARND 30KT...WHILE SFC FLOW IS LIGHT AND GENERALLY SOUTHERLY. THERE IS PLENTY OF LOW LEVEL MOISTURE IN PLACE AND WITH AT LEAST MODEST ISENTROPIC LIFT IN THE WARM SECTOR WHICH COULD AT LEAST GENERATE SCT SHRA/TSRA. THE LATEST HIGH RES GUIDANCE IS INDICATING A DIMINISHING TREND TO THE CONVECTION ALONG THE SRN PORTION OF THE FRONT AS IT MOVES THROUGH THE AREA THIS MORNING...SO HAVE BACKED OFF POPS TO SLIGHT CHANCE...BUT WITH DAYTIME WARMING...THERE SHOULD BE AN UPTICK IN THE CONVECTIVE ACTIVITY AD THE FRONT PUSHES THROUGH THE SRN PORTIONS OF THE CHICAGO METRO AREA AND INTO ECNTRL IL AND NWRN INDIANA. PORTIONS OF THE CWA. WITH INCREASING SLWY DEVELOPING WITH THE APPROACH OF THE COLD FRONT AND VEERING TO WLY FOLLOWING THE FROPA...NO LAKE BREEZE DEVELOPMENT IS EXPECTED TODAY AND THE WARM AIR SHOULD HAVE NO TROUBLE REACHING RIGHT UP TO THE LAKEFRONT...WITH TEMPS IN THE LOWER TO MIDDLE 80S EXPECTED FOR THE ENTIRE CWA. ANY RESIDUAL PCPN ASSOCIATED WITH THE PASSING COLD FRONT SHOULD PUSH TO THE EAST OF THE CWA BY LATE THIS EVENING. WEAK HIGH PRESSURE SHOULD BUILD IN BEHIND THE FRONT WEDNESDAY EVENING AND OVERNIGHT. WITH GENERALLY WLY FLOW BEHIND THE FRONT...AND NO SGFNT DRY AIR UPSTREAM...THE LOW LEVELS SHOULD REMAIN VERY MOIST...SO FOG DEVELOPMENT LATE TUESDAY NIGHT AND POSSIBLY INTO WEDNESDAY MORNING IS A DISTINCT POSSIBILITY. KREIN WEDNESDAY THROUGH THURSDAY... MAIN FEATURE IN THE MEDIUM TERM WILL BE THE DEPARTING MID-LVL VORT FROM THE GREAT LAKES...STEADILY WEAKENING AND EJECTING EAST. MEANWHILE A DEVELOPING 500MB RIDGE WILL TAKE SHAPE ACROSS THE PLAINS...THEN LIFT NORTHEAST THUR. THE STALLED FRONTAL BOUNDARY WILL REMAIN SOUTH OF THE FORECAST AREA THRU WED THEN AS THE RIDGE STEADILY BUILDS AND EXPANDS NORTH WARM AIR ADVECTION WILL LIFT THE BOUNDARY NORTH. THIS WILL LIKELY FEATURE MOISTENING LLVLS WITH DECENT ISENTROPIC LIFT ALONG THE BOUNDARY...TO SUPPORT INCREASING POPS LATE WED FROM SOUTH TO NORTH. WHILE IT APPEARS FAVORABLE FOR A CHANNEL OF LIKELY POPS LATE WED-EARLY THUR...THERE IS SOME CONCERN THAT WE COULD QUICKLY BECOME CAPPED WITH A STRONG PUSH OF VERY WARM AIR ALOFT. SOME GUIDANCE IS SUGGESTING AFT 00Z 850MB THERMAL TEMPS RISE TO ARND 19-20 DEG C...WHICH COULD BE ENOUGH TO LIMIT COVERAGE/INTENSITY. HOWEVER IF THIS ENDS UP BEING SLIGHTLY COOLER ANY PRECIP THAT DOES DEVELOP COULD EASILY PRODUCE LOCALLY HEAVY RAINFALL...AS PWAT VALUES ARE EXPECTED TO RISE TO NEAR 1.7-2.0" OVERNIGHT. TEMPS WED WILL PUSH INTO THE MID 80S...HOWEVER IT IS PLAUSIBLE THAT A WEAK LK BREEZE COULD FORM EARLY IN THE AFTN AND KEEP THE NEARSHORE AREAS COOLER. WITH WARM AIR STEADILY ADVECTING NORTH INTO THE FORECAST AREA...EXPECT TEMPS TO REMAIN MILD OVERNIGHT IN THE MID/UPR 60S. IF CLOUDS AND PRECIP ARRIVE EARLIER WED EVE...THEN TEMPS MAY NOT DIP BELOW 70. THUR WILL FEATURE STEADILY RISING MID-LVL HEIGHTS AS THE ROBUST RIDGE ESTABLISHES ITSELF ACROSS A BULK OF OF THE REGION. THIS POSES CHALLENGES WITH PRECIP FOR THUR. GUIDANCE CONTINUES TO FAVOR A SHORTWAVE LIFTING NORTHEAST INTO THE UPPER MIDWEST WITH BETTER MID-LVL VORTICITY THEN SLIDING EAST ALONG THE NORTHERN PERIPHERY OF THE RIDGE...BEFORE DIVING SOUTHEAST TOWARDS THE EASTERN GREAT LAKES. THIS COUPLED WITH VERY WARM 850MB TEMPS NEARING 20 DEG C MAY RESULT IN A CAPPED ENVIRONMENT. CONFIDENCE IS NOT YET STRONG ENOUGH TO FURTHER REDUCE POPS THUR AFTN. DEPENDING ON CLOUDS/PRECIP THUR WILL STEER HOW WARM SFC TEMPS BECOME. GUIDANCE CONTINUES TO POINT TOWARDS MID/UPR 80S. DEW PTS WILL BE PUSHING INTO THE LOW 70S...WHICH THE COMBINATION OF TEMP/DEW PT COULD BE SUPPORTIVE OF HEAT INDEX VALUES NEARING THE MID 90S. CONCERN REMAINS FOR THUR NGT ON POPS...BUT MORE IMPORTANTLY ON POTENTIAL FOR HEAVY RAINFALL. PWAT VALUES CONTINUE TO HOVER ARND 2" WITH VERY WARM DEW PTS BETWEEN 72-74 DEG. WITH THE LACK OF A STRONG WIND FIELD...STORMS COULD BE SLOW MOVING AND EASILY PRODUCE LOCALLY HEAVY RAINFALL. OVERNIGHT LOWS MAY NOT DIP BELOW THE MID/UPR 70S...WHICH SETS THE STAGE FOR A POTENTIALLY HOT/HUMID DAY FRI. FRIDAY THROUGH EARLY NEXT WEEK... MID-LVL RIDGING CONTINUES TO BE PROGGED FOR THE FRI-SUN PERIODS...WHICH SETS THE STAGE FOR POTENTIALLY A VERY WARM STRETCH ACROSS THE REGION WITH NUMEROUS AREAS REACHING 90 DEG IN THIS TIMEFRAME. GUIDANCE CONTINUES TO FAVOR A HIGH PROBABILITY THAT DEW PTS WILL EASILY REMAIN IN THE 72-74 DEG RANGE FRI/SAT...WHICH COUPLED WITH TEMPS ARND 90 COULD EASILY PRODUCE 100 DEG HEAT INDEX READINGS. THE CURRENT ECMWF SOLUTION PAINTS AN EVEN WARMER THERMAL RIDGE AT 850MB FOR SUN AT 23-25 DEG C. CLOUDS/PRECIP WILL LIKELY STEER HOW WARM SUN BECOMES. THEN ENSEMBLES CONTINUE TO DEMONSTRATE SOME CONSISTENCY THAT THE MID-LVL RIDGE WILL WEAKEN EARLY NEXT WEEK WITH A RETURN TO TROUGHING ACROSS THE MIDDLE OF THE CONUS. CURRENT GUIDANCE SUGGESTS A FRONTAL BOUNDARY WILL ARRIVE IN THE MON/TUE TIMEFRAME AND BRING TEMPS BACK TO SEASONAL OR SLIGHTLY SUB-SEASONAL CONDS FOR THE MIDDLE OF NEXT WEEK. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * CHANCE FOR SHRA/TSRA MID DAY THROUGH EARLY AFTERNOON...WITH BETTER CHANCES FOR MDW. * SWLY-WLY WINDS GUSTING TO 20 KT THROUGH EARLY EVENING. * POTENTIAL FOR MVFR VIS IN BR LATE TONIGHT INTO WED MORNING. KREIN/RODRIGUEZ //DISCUSSION...UPDATED 12Z... THE UPPER LEVEL DISTURBANCE THAT BROUGHT THE SHRA/TSRA TO SRN WI AND NRN IL HAS MOVED INTO LOWER MICHIGAN AND THAT PCPN HAS MOVED AWAY FROM THE REGION. THE TRAILING COLD FRONT IS LAGGING SW ACROSS THE AREA FROM NEAR UGN INTO SERN IA AT 12Z. SCT SHRA/TSRA HAVE DEVELOPED ALONG THE FRONT...MOVING THROUGH THE ORD AREA BTWN 1100-1130Z. THIS ACTIVITY IS ALSO DISSIPATING AS IT MOVES EWD AND EXPECT THAT THE TERMINALS...WITH THE EXCEPTION OF GYY SHOULD BE DRY FOR THE REMAINDER OF THE MORNING. THERE IS STILL SOME CONCERN THAT ADDITIONAL TSRA WILL IGNITE ALONG THE BOUNDARY BY LATE MORNING OR EARLY AFTERNOON AS IT MOVES INTO NWRN IN-ECNTRL IL. DIURNAL WARMING AND WEAK SFC CONVERGENCE SHOULD HELP ORGANIZE THE DEVELOPMENT...BUT ANTICIPATE THAT IT SHOULD BE TO THE EAST OF THE TERMINALS...WITH THE POSSIBLE EXCEPTION OF GYY BY THE TIME THE ACTIVITY REDEVELOPS. AS FOR WINDS...LIGHT SWLY WINDS WILL CONTINUE IN ADVANCE OF THE WEAK COLD FRONT...AND INCREASE THROUGH THE MORNING AS THE SFC PRESSURE GRADIENT STRENGTHENS. BY LATE MORNING...SWLY WINDS SHOULD INCREASE TO 10-15KT WITH OCNL GUSTS OF 20KT PERSISTING THROUGH EARLY EVENING WHILE GRADUALLY VEERING TO WESTERLY BY LATE AFTERNOON UNTIL AROUND SUNSET. HIGH PRESSURE BUILDING IN OVERNIGHT TONIGHT SHOULD BRING DECREASING CLOUD COVER AND DIMINISHING WINDS. WITH AMPLE RESIDUAL MOISTURE EXPECT AT LEAST PATCHY FOG TO DEVELOP AFTER MIDNIGHT. THERE IS THE POTENTIAL FOR VIS TO DROP TO IFR...BUT THERE IS A CHANCE THAT THERE COULD BE SOME RESIDUAL CLOUD COVER FROM CONVECTIVE ACTIVITY CURRENTLY MOVING THROUGH MISSOURI COULD LIMIT THE VIS DROPPING...SO WILL ONLY GO 3-4SM BR FOR NOW. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * LOW MEDIUM CONFIDENCE FOR TSRA/SHRA TO IMPACT ORD...MEDIUM HIGH CONFIDENCE FOR TSRA/SHRA TO IMPACT MDW MID DAY THROUGH EARLY AFTERNOON. * MEDIUM TO HIGH CONFIDENCE IN WIND SPEED AND DIRECTION. * MEDIUM CONFIDENCE IN MVFR VIS OCCURRING LATE TONIGHT INTO WEDNESDAY MORNING. LOW CONFIDENCE IN CHANCES FOR IFR VIS. KREIN/RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR TSRA AND OCNL REDUCED CIGS/VIS. SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL. && .MARINE... 316 AM CDT AN AREA OF LOW PRESSURE OVER CENTRAL WISC WILL CONTINUE TO DRIFT NORTHEAST ACROSS THE NORTHERN PORTION OF THE LAKE MIDDAY...THEN CONTINUE TO SLIDE EAST AND WEAKEN WEDNESDAY AFTERNOON ACROSS SOUTHEAST ONTARIO. THE GRADIENT IS EXPECTED TO TIGHTEN SLIGHTLY FROM THE SOUTH...WITH WINDS INCREASING THIS MORNING TO ARND 15 TO 25KT. THEN AS THE LOW SLIDES EAST WINDS WILL BECOME WEST AND DIMINISH TO ARND 10 TO 20 KT LATE TONIGHT. WAVES SHUD BE ABLE TO BRIEFLY BUILD ACROSS THE LAKE TO ARND 2-4FT...THEN WITH A LIGHTER GRADIENT ARRIVING WED WAVES WILL SUBSIDE TO ARND 2 FT OR LESS. IN THE DEPARTING SFC LOW WILL BE A MUCH WEAKER GRADIENT...WITH WINDS GENERALLY LIGHT FROM THE NORTH ARND 5 TO 10 KT ACROSS THE NORTHERN HALF OF THE LAKE AND AROUND 10 KT FROM THE SOUTH FOR THE SOUTHERN HALF OF THE LAKE. A WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE SOUTHERN PORTION OF THE LAKE EARLY THUR...WITH MUCH WARMER AIR LIFTING OVER THE LAKE. AT THIS TIME FEEL THAT FOG MAY NOT DEVELOP...BUT COULD SEE SOME HAZY CONDITIONS DEVELOP LATE IN THE WEEK. SOUTH/SOUTHEAST WINDS FOR THE WEEKEND. THE UPPER FLOW PATTERN DOES LOOK TO SHIFT SUNDAY OR MONDAY BRINGING A COLD FRONT ACROSS THE LAKE WITH A SHIFT TO NORTHERLY WINDS WHICH MAY BE RATHER BREEZY EARLY NEXT WEEK. BEACHLER && .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 923 AM CDT Tue Aug 19 2014 .UPDATE... ISSUED AT 923 CDT TUE AUG 19 2014 Area of showers and thunderstorms associated with an upper-level wave is currently crossing the Mississippi River into west-central Illinois. 1417z radar imagery shows leading edge of precip extending from Galesburg...to Rushville...to Bowling Green Missouri. Based on timing tools, showers/thunder will arrive along the I-55 corridor by midday. HRRR and other high-res models generally show the precip area weakening as it pushes eastward through the morning, then potentially re-developing across east-central Illinois later this afternoon. Made some adjustments to hourly PoPs today, mainly to increase to categorical along/west of I-55 during the morning. Once the wave passes, rain chances will come to an end across the Illinois River Valley by mid to late afternoon, followed by a return to partly to mostly sunny skies. Further east, rain chances will linger throughout the day before coming to an end by evening. && .SHORT TERM...(This afternoon through Wednesday) ISSUED AT 336 AM CDT TUE AUG 19 2014 Short term models have trended slower with the front and precip that is currently supposed to be moving into the area. But will still have chance of precip starting in the northwest parts of the cwa this morning. Then will progress the pcpn chances southeastward across the cwa during the day. By this evening, most of the pcpn will be in the eastern two thirds of the area with the highest pops in the southeast. By overnight, the pcpn should have moved southeast of the area so most of the area should be dry overnight, though will keep a slight chance of pops in the southeast after midnight. Could be some additional pcpn in the southwest late tonight, but models keep most of pcpn west of the area through 12z. Temps will begin the slow warming tomorrow, and am expecting mid to upper 80s throughout the area today. && .LONG TERM...(Wednesday night through Monday) ISSUED AT 347 AM CDT TUE AUG 19 2014 Models still pretty consistent with the development and lift of a boundary through the Midwest on Wednesday. Boundary will have little reflection at the sfc with very weak flow/weak wind shift, and thermal gradient is better represented in the mid levels. Boundary will provide a weak focus for waves moving through the region as the boundary lifts to the NE through the area for Wed/Wed night. Though Wed is lacking signif pop for now, the timing of the progression is better for early evening and into the overnight on Wednesday night/shifting to the northeast for Thurs. Position of the boundary or the remnants thereof will be where the majority of the precip chances will be...increasing to the north, particularly north of Interstate 74 from Thursday to Saturday. Ample sfc based instability in the form of hot and humid conditions as the ridge over the southwest opens and spreads signif heat into the Midwest. Models have also shown consistency with 850 mb temps in the 19-25C range from Wednesday through Sunday. This will drive the temps into the upper 80s/lower 90s with heat indices in the upper 90s/approaching 100F. A far more summer-like pattern than much of the season so far, and well above normal for this time of year...with breaks from the heat provided by any thunderstorms that may have the chance to form from more diurnal instability with any frontal forcing further to the north. Into the extended, day 7/just into day 8, models diverge in solutions with major difference in breaking down the upper ridge for the Midwest. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) ISSUED AT 609 AM CDT TUE AUG 19 2014 Cold front is still back northwest of the area, but still forecasted to move through the area, affecting all TAF sites this through afternoon. However, radar loops show a complex of thunderstorms in northern MO that could move into central IL this morning and effect some of the TAF sites, possibly SPI and DEC. Short term models do show some pcpn moving through the area this morning, but appears it will diminish as it moves into the area. Then the front drops into the area a few hours later and this will bring a chance of thunderstorms to the TAF sites for the afternoon and early evening. The early stuff could be just showers, but since the front will be right on the heels of the current complex coming out of MO, will opt to just have VCTS for all TAFs to cover both events. Believe t-storms will be more scattered as well. Also VCTS will be in the TAFs longer than necessary, but only because of two events. Not expecting cigs to go down today, but having some light fog issues at mainly CMI, with some very light fog at PIA and BMI. This fog will burn off quickly, like yesterday morning. Winds will be south to southwest through the morning and then become southwest just ahead of the front, and then westerly or light and variable after FROPA. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...AUTEN LONG TERM...HJS AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
604 PM CDT TUE AUG 19 2014 .SYNOPSIS... ISSUED AT 305 PM CDT TUE AUG 19 2014 WEAK HIGH PRESSURE OVER IOWA WILL MOVE EAST AS A WARM FRONT DEVELOPS TO THE SOUTH AND BEGINS TO LIFT NORTH TONIGHT. THE FRONT WILL LIFT NORTH OF THE STATE ON WEDNESDAY NIGHT. STRONG S/WV WILL MOVE UP THE BACK SIDE OF THE UPPER LEVEL RIDGE AND PUSH A COLD FRONT ACROSS THE STATE THIS WEEKEND. && .SHORT TERM /TONIGHT/... ISSUED AT 305 PM CDT TUE AUG 19 2014 A SURFACE LOW DEVELOPING OVER NORTHEAST COLORADO WILL SHIFT INTO NORTHWEST NEBRASKA OVERNIGHT. AN ASSOCIATED WARM FRONT WILL EXTEND FROM THE LOW THROUGH EASTERN NEBRASKA AND INTO SOUTHWEST IOWA AND NORTHERN MISSOURI BY 12Z WEDNESDAY BEFORE SURGING NORTH THROUGH THE DAY WEDNESDAY. STRONG THETA-E ADVECTION IS FORECAST TO LIFT ACROSS CENTRAL IOWA DURING THE OVERNIGHT HOURS...ESPECIALLY AFTER 06Z. FORCING IS WEAK BUT DOES IMPROVE OVERNIGHT AS A LOW LEVEL JET FOCUSES INTO SOUTHWEST IOWA. ALOFT A WEAK SHORTWAVE IS PROGGED TO MOVE ACROSS EASTERN NEBRASKA/SOUTHWEST IOWA. THIS SHOULD BE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS SOUTHWEST INTO CENTRAL IOWA. STORMS SHOULD MAINLY BE ELEVATED AS LOW LEVEL CONVERGENCE IS WEAK TO NON EXISTENT. THERE IS ALSO SOME WEAK SHEAR...PERHAPS ENOUGH FOR AN ISOLATED STORM TO BRIEFLY PRODUCE SOME MARGINALLY SEVERE TO SEVERE HAIL. THE HIGH RES AND NAM12 MODELS ARE NOT AS IMPRESSIVE WITH DEVELOPING STORMS ACROSS THE AREA BUT THE SREF DOES AS DOES PREVIOUS RUN OF THE HI-RES MODELS. THE HRRR IN PARTICULAR IS FAIRLY BULLISH ON BRINING PRECIP INTO THE SW WHILE THE MEMBERS OF THE HOPWRF ARE A LITTLE MORE RESERVED...AT LEAST THROUGH 09Z. SOME POTENTIAL FOR FOG ACROSS THE NORTHEAST OVERNIGHT AS REMAINING CLOUDS ACROSS THE AREA DISSIPATE WITH SUNSET AND SURFACE RIDGING MOVES OVERHEAD PRODUCING LIGHT WIND. NOT LOOKING AT DENSE FOG AT THIS POINT GIVEN THE VERY SHALLOW NATURE OF THE MOISTURE MOVING IN. GENERALLY WENT WITH PATCHY FOG WORDING HOWEVER ALO/MCW WILL BE EAST OF THE RIDGE AXIS AND MOISTURE COULD BE ENOUGH FOR A LITTLE MORE WIDESPREAD FOG SO I MENTION AREAS OF FOG OVER THESE LOCATIONS. .LONG TERM /WEDNESDAY THROUGH TUESDAY/... ISSUED AT 305 PM CDT TUE AUG 19 2014 A BREAK IN THE CONVECTION IS EXPECTED ON WED AS THE FIRST ROUND OF THETA-E ADVECTON LIFTS OUT OF THE STATE. A RENEWED THREAT OF THUNDERSTORMS WILL COME AS THE WARM FRONT LIFTS NORTH AND STRONG THETA-E ADVECTION TAKES PLACE WED NIGHT. THE H8 SHOWS GOOD SPEED CONVERGENCE AND THERE IS DIVERGENCE ALOFT...THE FLY IN THE OINTMENT WILL BE IF THE ATMOSPHERE CAPS OFF OR NOT. AN EML IS IN PLACE...BUT IT IS NOT ALL THAT STRONG. WARM AND HUMID WEATHER WILL HOLD INTO THE WEEKEND WITH AFTERNOON HEAT INDICES IN THE LOW TO MID 90S NORTH...AND 95 TO 105 SOUTH TUE-THU AFTERNOON. BELOW CRITERIA...BUT WILL MENTION IN THE HWO WITH ALL THE SCHOOL ACTIVITIES GOING ON. COOLER WEATHER WILL MOVE IN OVER THE WEEKEND...FIRST DUE TO THE INCREASED CLOUD COVER...THEN DUE TO THE FRONTAL PASSAGE SAT. COOL AIR WILL SETTLE IN SLOWLY WITH TEMPS FALLING BELOW NORMAL; FOR MON AND TUE. && .AVIATION...20/00Z ISSUED AT 601 PM CDT TUE AUG 19 2014 BOUNDARY LIFTING NORTH ACROSS CENTRAL IOWA MAY AFFECT SITES WITH SHRA/TSRA AT TIMES NEAR 12Z. CONDITIONS MAY DROP TO MVFR OR IFR AT TIMES WITH TSRA AT SITES...HAVE ONLY INCLUDED AT SOUTHERN SITES...KFOD/KDSM/KOTM ATTM. IN ADDITION...BR OR FG MAY DEVELOP WITH LIGHT WINDS AT NORTHERN SITES NEAR 12Z BRINGING CONDITIONS DOWN TO MVFR OR IFR. CONDITIONS WILL IMPROVE QUICKLY BEYOND 12Z WITH WINDS BECOMING SOUTHERLY AND VFR CONDITIONS EXPECTED AGAIN. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MS AUG 14 SHORT TERM...FAB LONG TERM...MS AUG 14 AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 PM CDT TUE AUG 19 2014 .SYNOPSIS... ISSUED AT 305 PM CDT TUE AUG 19 2014 WEAK HIGH PRESSURE OVER IOWA WILL MOVE EAST AS A WARM FRONT DEVELOPS TO THE SOUTH AND BEGINS TO LIFT NORTH TONIGHT. THE FRONT WILL LIFT NORTH OF THE STATE ON WEDNESDAY NIGHT. STRONG S/WV WILL MOVE UP THE BACK SIDE OF THE UPPER LEVEL RIDGE AND PUSH A COLD FRONT ACROSS THE STATE THIS WEEKEND. && .SHORT TERM /TONIGHT/... ISSUED AT 305 PM CDT TUE AUG 19 2014 A SURFACE LOW DEVELOPING OVER NORTHEAST COLORADO WILL SHIFT INTO NORTHWEST NEBRASKA OVERNIGHT. AN ASSOCIATED WARM FRONT WILL EXTEND FROM THE LOW THROUGH EASTERN NEBRASKA AND INTO SOUTHWEST IOWA AND NORTHERN MISSOURI BY 12Z WEDNESDAY BEFORE SURGING NORTH THROUGH THE DAY WEDNESDAY. STRONG THETA-E ADVECTION IS FORECAST TO LIFT ACROSS CENTRAL IOWA DURING THE OVERNIGHT HOURS...ESPECIALLY AFTER 06Z. FORCING IS WEAK BUT DOES IMPROVE OVERNIGHT AS A LOW LEVEL JET FOCUSES INTO SOUTHWEST IOWA. ALOFT A WEAK SHORTWAVE IS PROGGED TO MOVE ACROSS EASTERN NEBRASKA/SOUTHWEST IOWA. THIS SHOULD BE ENOUGH TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS SOUTHWEST INTO CENTRAL IOWA. STORMS SHOULD MAINLY BE ELEVATED AS LOW LEVEL CONVERGENCE IS WEAK TO NON EXISTENT. THERE IS ALSO SOME WEAK SHEAR...PERHAPS ENOUGH FOR AN ISOLATED STORM TO BRIEFLY PRODUCE SOME MARGINALLY SEVERE TO SEVERE HAIL. THE HIGH RES AND NAM12 MODELS ARE NOT AS IMPRESSIVE WITH DEVELOPING STORMS ACROSS THE AREA BUT THE SREF DOES AS DOES PREVIOUS RUN OF THE HI-RES MODELS. THE HRRR IN PARTICULAR IS FAIRLY BULLISH ON BRINING PRECIP INTO THE SW WHILE THE MEMBERS OF THE HOPWRF ARE A LITTLE MORE RESERVED...AT LEAST THROUGH 09Z. SOME POTENTIAL FOR FOG ACROSS THE NORTHEAST OVERNIGHT AS REMAINING CLOUDS ACROSS THE AREA DISSIPATE WITH SUNSET AND SURFACE RIDGING MOVES OVERHEAD PRODUCING LIGHT WIND. NOT LOOKING AT DENSE FOG AT THIS POINT GIVEN THE VERY SHALLOW NATURE OF THE MOISTURE MOVING IN. GENERALLY WENT WITH PATCHY FOG WORDING HOWEVER ALO/MCW WILL BE EAST OF THE RIDGE AXIS AND MOISTURE COULD BE ENOUGH FOR A LITTLE MORE WIDESPREAD FOG SO I MENTION AREAS OF FOG OVER THESE LOCATIONS. .LONG TERM /WEDNESDAY THROUGH TUESDAY/... ISSUED AT 305 PM CDT TUE AUG 19 2014 A BREAK IN THE CONVECTION IS EXPECTED ON WED AS THE FIRST ROUND OF THETA-E ADVECTON LIFTS OUT OF THE STATE. A RENEWED THREAT OF THUNDERSTORMS WILL COME AS THE WARM FRONT LIFTS NORTH AND STRONG THETA-E ADVECTION TAKES PLACE WED NIGHT. THE H8 SHOWS GOOD SPEED CONVERGENCE AND THERE IS DIVERGENCE ALOFT...THE FLY IN THE OINTMENT WILL BE IF THE ATMOSPHERE CAPS OFF OR NOT. AN EML IS IN PLACE...BUT IT IS NOT ALL THAT STRONG. WARM AND HUMID WEATHER WILL HOLD INTO THE WEEKEND WITH AFTERNOON HEAT INDICES IN THE LOW TO MID 90S NORTH...AND 95 TO 105 SOUTH TUE-THU AFTERNOON. BELOW CRITERIA...BUT WILL MENTION IN THE HWO WITH ALL THE SCHOOL ACTIVITIES GOING ON. COOLER WEATHER WILL MOVE IN OVER THE WEEKEND...FIRST DUE TO THE INCREASED CLOUD COVER...THEN DUE TO THE FRONTAL PASSAGE SAT. COOL AIR WILL SETTLE IN SLOWLY WITH TEMPS FALLING BELOW NORMAL; FOR MON AND TUE. && .AVIATION...19/18Z ISSUED AT 1247 PM CDT TUE AUG 19 2014 WARMER AIR WILL MOVE INTO CENTRAL IOWA FROM THE SW...ALONG WITH SOME MOISTURE AND INSTABILITY AS A WARM FRONT TRIES TO ESTABLISH ITSELF OVER NEB AND KS THEN LIFT INTO IA LATER THIS EVENING/OVERNIGHT. SOME SHOWERS/TSRA ARE POSSIBLE MAINLY FM KDSM-KOTM BUT MAY MAKE IT AS FAR NORTH AS KFOD. WITH LOW LEVEL MOISTURE INCREASING...COULD ALSO SEE SOME FOG...ESPECIALLY NORTHEAST AFT 08Z. MVFR VSBYS POSSIBLE IN THE FOG. VFR CONDITIONS SHOULD AGAIN PREVAIL AFTER 13- 15Z. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MS AUG 14 SHORT TERM...FAB LONG TERM...MS AUG 14 AVIATION...FAB
AREA FORECAST DISCUSSION
NWS PADUCAH KY
ISSUED BY NATIONAL WEATHER SERVICE LOUISVILLE KY 1250 PM CDT Tue Aug 19 2014 .UPDATE... Issued at 1250 PM CDT TUE AUG 19 2014 The AVIATION section has been updated for the 18Z TAF issuance. UPDATE Issued at 1121 AM CDT TUE AUG 19 2014 The fog and low clouds have dissipate, leaving behind just a scattered cu deck late this morning. An area of convection has weakened significantly since 15Z as it moved eastward into the KSTL area. However, it did push an outflow boundary eastward and it is only a county or so northwest of our area as of 16Z. Not sure whether the boundary will survive as it moves into the strong mixing in our region or not, but figure it or just a differential heating boundary may focus thunderstorm development possibly by 18Z in the KMVN and KMDH areas. The latest HRRR and 12Z NAM runs develop convection over much of southern Illinois and push it southeast through southwest Indiana and much of west Kentucky through the late afternoon and early evening hours. The southwestward extent of development is in doubt due to a very strong capping inversion noted on the 12Z KSGF RAOB. The forecast has been updated to account for these convective trends. Capped PoPs in the northeast at 50% due to the potential for the cap to hold even up there. Also, kept a slight chance in the far west just in case the cap does not hold. The NAM soundings indicate that there will be some fairly steep mid-level lapse rates for storms to feed on, if the cap can be broken. Wind fields will be increasing, but the best winds may lag the convection through the area. Given the instability alone, figure that a few storms will reach severe criteria with winds and hail the primary concerns. && .SHORT TERM...(Today through Thursday night) Issued at 214 AM CDT TUE AUG 19 2014 Short term weather continues to be somewhat active. Aside from patchy/areas of dense fog early this morning, only a few high clouds are expected to track across the region. An MCS located over north central Kansas at the time of this writing should weaken considerably on its southeast trek, and should there be anything left of it later this morning, it should pass by to our south and west. Precipitation chances are expected to make their way into the forecast this afternoon as a short wave pushes a weak cold front toward the lower Ohio valley. Due to lack of deeper moisture models not showing much in the way of convection before 18Z, but after that precipitation chances should begin to increase from the northwest with the approach of the aforementioned boundary. With decent flow aloft over a moderately unstable airmass in place, a few storms could become strong to severe Tuesday afternoon into the evening hours, especially over most of southern Illinois and northwest Kentucky, and all of southwest Indiana. Large hail and damaging winds will be the primary threats. Models show the short wave outrunning the surface boundary late Tuesday night, and with H5 heights beginning to increase at that point, the boundary never quite makes it into our CWA and gets pushed back to the north and east as a warm front. Precipitation chances will begin to diminish from southwest to northeast on Wednesday as an upper ridge over the southern plains begins to build northeast across our region . This trend will continue through Thursday as the ridge continues to overspread the area. At this time it looks like Thursday night will be dry as the upper ridge takes control. Unfortunately with the approach of the ridge, the resultant compression/warming of the air will raise temperatures to near normal levels (mid 90s) the latter half of the short term period. This combined with dewpoints around 70 degrees will produce heat indices near the century mark for most if not all of our CWA both Wednesday and Thursday afternoon. .LONG TERM...(Friday through Monday) Issued at 214 AM CDT TUE AUG 19 2014 The long term will be dominated by an upper level ridge over the Lower and Middle Mississippi Valley. This will help to stabilize the atmosphere as the tropospheric profile undergoes a drying trend. Consequently, any slight chance for showers and thunderstorms will likely be shunted north and east of the immediate forecast area through the weekend. The main concern during this time will be the heat and humidity as the hottest weather of the year takes hold. Highs in the mid to upper 90s will combine with relatively high humidity to push heat index readings to the 100 to 105 degree range each afternoon. Given the anticipated prolonged nature of this event, I see little reason why a Heat Advisory will not be issued later this week for peak afternoon heat indices between 100 and 105 for at least four consecutive days. Will continue to monitor and adjust forecast as necessary. && .AVIATION... Issued at 1250 PM CDT TUE AUG 19 2014 An outflow boundary is expected to provide a focus for thunderstorm development over southern Illinois this afternoon. Best guess is that the storms would impact KEVV and KOWB around 00Z. With plentiful low-level moisture, fog development will be possible again tonight, but with some southwest wind expected, LIFR/VLIFR conditions are less likely. If they occur it would most likely be at KCGI. Just a few cu expected by midday Wednesday, along with modest west southwest to west winds. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...JP LONG TERM...RJP AVIATION...DRS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
106 PM CDT TUE AUG 19 2014 .AVIATION... FOR THE 19/18Z TAFS...SCATTERED CONVECTION BEGINNING TO DEVELOP IN ASSOCIATION WITH A WEAK SHEAR AXIS AND MID LVL TROUGH OVER CNTRL TX. HAVE VCTS AREAWIDE THIS AFTERNOON BUT SHWRS/TSTMS SHOULD BE MOSTLY UNORGANIZED AND SPOTTY. WITH THE EXCEPTION OF KLFK...DIRECT IMPACTS ON THE TAF SITES ARE TOO UNCERTAIN TO PREVAIL OR TEMPO PRECIP SO AMENDMENTS MAY BE NEEDED LATER THIS AFTERNOON. VFR CONDITIONS SHOULD PREVAIL ALTHOUGH MVFR OR LOWER CONDITIONS WILL BE POSSIBLE WHERE CONVECTION IS ONGOING. SHWRS/TSTMS EXPECTED TO SLOWLY DISSIPATE AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. MOIST SLY FLOW SHOULD RESULT IN A BRIEF WINDOW OF LOW STRATUS AROUND SUNRISE WEDNESDAY MORNING MAINLY ALONG AND SOUTH OF I-20 WITH CIGS LIFTING LATE IN THE PERIOD. /09/ && .PREV DISCUSSION... /ISSUED 1109 AM CDT TUE AUG 19 2014/ DISCUSSION... HAVE BUMPED UP THE DAYTIME HIGHS FOR MUCH OF THE FOUR STATE AREA TODAY GIVEN THE CURRENT TREND SHOWS WARMING ABOUT 2 TO 3 DEGREES FASTER TODAY THAN YESTERDAY. MINOR ADJUSTMENTS TO THE DEW POINTS AND WINDS. NO OTHER SIGNIFICANT CHANGES TO THE FORECAST. /06/ PREV DISCUSSION... /ISSUED 423 AM CDT TUE AUG 19 2014/ DISCUSSION... THE MORNING WATER VAPOR IMAGERY INDICATES THAT THE MAIN SHORTWAVE THAT PRODUCED EXTENSIVE CONVECTION JUST 24 HRS AGO OVER SW AR/EXTREME NRN LA HAS SHIFTED E INTO NRN GA...WITH THE 00Z RAOB 500MB PLOT STILL REVEALING A WEAK SHEAR AXIS THAT EXTENDS FARTHER W ACROSS NRN MS/N LA AND INTO NE TX. MEANWHILE...MOSAIC RADAR IMAGERY ALSO INDICATES A WELL-DEFINED MCV SPINNING E OF SJT...WHICH THE 00Z PROGS HAVE INITILIZED WELL ON AS CONVECTION CONTINUES TO REGENERATE NEAR AND E OF THE CENTER OVER CNTRL TX. THIS CONVECTION HAS PRODUCED A THICK AC CANOPY OVER NE TX/EXTREME NW LA...ALTHOUGH IR IMAGERY DEPICTS WARMING CLOUD TOPS SUGGESTING A WEAKENING TREND IS ONGOING ATTM. THIS MCV CENTER IS PROGGED TO DRIFT NNE ACROSS NCNTRL TX TODAY...WHICH COULD MAINTAIN ELEVATED CONVECTIVE DEBRIS OVER THE NRN HALF OF THE AREA THROUGH AT LEAST THE FIRST HALF OF THE DAY...BEFORE POSSIBLY THINNING THIS AFTERNOON. MY FORECAST MAX TEMPS MAY BE A BIT HIGH TODAY ESPECIALLY IF THIS DEBRIS FIELD HANGS TOUGH TODAY...BUT HAVE PLAYED THE PESSIMIST WITH IT THINNING LATER TODAY...ESPECIALLY AS 09Z TEMPS REMAIN IN THE MID/UPPER 70S. WHILE THE SHORT TERM PROGS DO SUGGEST A WEAK SEABREEZE AFFECTING DEEP E TX/SRN SECTIONS OF NCNTRL LA THIS AFTERNOON...ONLY THE LATEST HRRR RUN DEPICTS AT LEAST ISOLATED CONVECTION DEVELOPING THIS AFTERNOON ALONG THE RESIDUAL SHEAR AXIS...WHICH IS STILL WEAKLY REFLECTED IN THE OTHER SHORT RANGE PROGS. IN ADDITION...THE 09Z SFC ANALYSIS INDICATES A DISTINCT W-E GRADIENT IN SFC THETA-E FROM NEAR OSA TO ALONG THE AR/LA LINE...INDICATIVE OF THE WEAK COLD POOL FROM CONVECTION THAT AFFECTED THESE AREAS MONDAY AFTERNOON/EVENING. GIVEN THESE WEAK SFC AND UPPER AIR FORCING MECHINISMS...AND THE FACT THAT THE CNTRL TX MCV IS PROGGED TO LIFT NNE ACROSS THE STATE TODAY...HAVE EXPANDED SLIGHT CHANCE POPS TO COVER MUCH OF THE REGION THIS AFTERNOON...AND DID CARRY THEM THROUGH THE EVENING BEFORE THEY DIMINISH WITH THE STABILIZING BNDRY LYR. THE SHEAR AXIS IS EXPECTED TO WASH OUT OVERNIGHT WITH THE MCV OPENING UP LATE...AS THE WRN ATLANTIC/CNTRL GULF OF MX UPPER RIDGE EXPECTED TO BRIDGE NWD INTO THE LOWER MS VALLEY WEDNESDAY. STILL SHOULD SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES WEDNESDAY AND THURSDAY AFTERNOONS/EARLY EVENINGS...BEFORE THE UPPER RIDGE CENTER BECOMES ESTABLISHED OVER THE MID-SOUTH/LOWER MS VALLEY FRIDAY. BOTH THE GFS AND ECMWF AMPLIFY THE RIDGE FARTHER N ACROSS THE SRN PLAINS/MS VALLEY FRIDAY...AND KEEPS IT PERSISTENT THROUGH THE WEEKEND INTO EARLY NEXT WEEK. INCREASED SUBSIDENCE WILL RESULT IN MAX TEMPS CLIMBS INTO THE UPPER 90S AREAWIDE...WITH EVEN SOME TRIPLE DIGITS POSSIBLE OVER SOME AREAS THIS WEEKEND/EARLY NEXT WEEK. THE MEDIUM RANGE PROGS DO BEGIN TO SLOWLY NUDGE THE RIDGE E INTO THE SE STATES BY TUESDAY/WEDNESDAY...WITH WEAKNESSES RIDING W BENEATH THE RIDGE ACROSS S LA/SRN MS AS EARLY AS MONDAY. THUS...ISOLATED CONVECTION WILL BE POSSIBLE OVER NCNTRL LA MONDAY AFTERNOON...BEFORE SPREADING FARTHER WNW TO ENCOMPASS MUCH OF THE REGION BY THE END OF THE EXTENDED. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 96 76 97 / 10 10 10 10 10 MLU 95 73 96 74 97 / 20 20 10 10 10 DEQ 94 71 94 71 95 / 20 20 0 0 0 TXK 94 74 96 74 96 / 20 20 0 0 0 ELD 95 72 96 74 97 / 20 20 0 0 0 TYR 95 75 96 76 97 / 10 20 10 10 10 GGG 95 74 96 75 97 / 10 10 10 10 10 LFK 96 75 96 76 97 / 20 20 20 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1109 AM CDT TUE AUG 19 2014 .DISCUSSION... HAVE BUMPED UP THE DAYTIME HIGHS FOR MUCH OF THE FOUR STATE AREA TODAY GIVEN THE CURRENT TREND SHOWS WARMING ABOUT 2 TO 3 DEGREES FASTER TODAY THAN YESTERDAY. MINOR ADJUSTMENTS TO THE DEW POINTS AND WINDS. NO OTHER SIGNIFICANT CHANGES TO THE FORECAST. /06/ && .PREV DISCUSSION... /ISSUED 651 AM CDT TUE AUG 19 2014/ AVIATION... CONCERNING THE ARKLATEX...A LOT OF DEBRIS CIRRUS KEEPING STATION AND MITIGATING MVFR BOTH CIGS/FG. CONVECTION TODAY MAY OCCUR OVER THE SOUTH WITH RESPECT TO A WEAK SEA BREEZE PUSH AND OVER OUR NORTH ALONG A WEAK SHEAR AXIS WITH SOMEWHAT BETTER CHANCES FROM KTXK...TO KMLU AND MAY BRIEFLY AFFECT KELD AND KSHV THIS MID AFTERNOON BASED ON THE HIGH RES MODEL. VCTS FOR THE AFTERNOON HOURS WILL BE AMENDED WITH DEVELOPMENT. OTHERWISE S/SW WINDS ON THE SFC ARE GENERALLY SW- NW ALOFT WITH NOT MUCH SPEED ANYWHERE. /24/ PREV DISCUSSION... /ISSUED 423 AM CDT TUE AUG 19 2014/ DISCUSSION... THE MORNING WATER VAPOR IMAGERY INDICATES THAT THE MAIN SHORTWAVE THAT PRODUCED EXTENSIVE CONVECTION JUST 24 HRS AGO OVER SW AR/EXTREME NRN LA HAS SHIFTED E INTO NRN GA...WITH THE 00Z RAOB 500MB PLOT STILL REVEALING A WEAK SHEAR AXIS THAT EXTENDS FARTHER W ACROSS NRN MS/N LA AND INTO NE TX. MEANWHILE...MOSAIC RADAR IMAGERY ALSO INDICATES A WELL-DEFINED MCV SPINNING E OF SJT...WHICH THE 00Z PROGS HAVE INITILIZED WELL ON AS CONVECTION CONTINUES TO REGENERATE NEAR AND E OF THE CENTER OVER CNTRL TX. THIS CONVECTION HAS PRODUCED A THICK AC CANOPY OVER NE TX/EXTREME NW LA...ALTHOUGH IR IMAGERY DEPICTS WARMING CLOUD TOPS SUGGESTING A WEAKENING TREND IS ONGOING ATTM. THIS MCV CENTER IS PROGGED TO DRIFT NNE ACROSS NCNTRL TX TODAY...WHICH COULD MAINTAIN ELEVATED CONVECTIVE DEBRIS OVER THE NRN HALF OF THE AREA THROUGH AT LEAST THE FIRST HALF OF THE DAY...BEFORE POSSIBLY THINNING THIS AFTERNOON. MY FORECAST MAX TEMPS MAY BE A BIT HIGH TODAY ESPECIALLY IF THIS DEBRIS FIELD HANGS TOUGH TODAY...BUT HAVE PLAYED THE PESSIMIST WITH IT THINNING LATER TODAY...ESPECIALLY AS 09Z TEMPS REMAIN IN THE MID/UPPER 70S. WHILE THE SHORT TERM PROGS DO SUGGEST A WEAK SEABREEZE AFFECTING DEEP E TX/SRN SECTIONS OF NCNTRL LA THIS AFTERNOON...ONLY THE LATEST HRRR RUN DEPICTS AT LEAST ISOLATED CONVECTION DEVELOPING THIS AFTERNOON ALONG THE RESIDUAL SHEAR AXIS...WHICH IS STILL WEAKLY REFLECTED IN THE OTHER SHORT RANGE PROGS. IN ADDITION...THE 09Z SFC ANALYSIS INDICATES A DISTINCT W-E GRADIENT IN SFC THETA-E FROM NEAR OSA TO ALONG THE AR/LA LINE...INDICATIVE OF THE WEAK COLD POOL FROM CONVECTION THAT AFFECTED THESE AREAS MONDAY AFTERNOON/EVENING. GIVEN THESE WEAK SFC AND UPPER AIR FORCING MECHINISMS...AND THE FACT THAT THE CNTRL TX MCV IS PROGGED TO LIFT NNE ACROSS THE STATE TODAY...HAVE EXPANDED SLIGHT CHANCE POPS TO COVER MUCH OF THE REGION THIS AFTERNOON...AND DID CARRY THEM THROUGH THE EVENING BEFORE THEY DIMINISH WITH THE STABILIZING BNDRY LYR. THE SHEAR AXIS IS EXPECTED TO WASH OUT OVERNIGHT WITH THE MCV OPENING UP LATE...AS THE WRN ATLANTIC/CNTRL GULF OF MX UPPER RIDGE EXPECTED TO BRIDGE NWD INTO THE LOWER MS VALLEY WEDNESDAY. STILL SHOULD SEE A WEAK SEABREEZE AFFECTING THE SRN ZONES WEDNESDAY AND THURSDAY AFTERNOONS/EARLY EVENINGS...BEFORE THE UPPER RIDGE CENTER BECOMES ESTABLISHED OVER THE MID-SOUTH/LOWER MS VALLEY FRIDAY. BOTH THE GFS AND ECMWF AMPLIFY THE RIDGE FARTHER N ACROSS THE SRN PLAINS/MS VALLEY FRIDAY...AND KEEPS IT PERSISTENT THROUGH THE WEEKEND INTO EARLY NEXT WEEK. INCREASED SUBSIDENCE WILL RESULT IN MAX TEMPS CLIMBS INTO THE UPPER 90S AREAWIDE...WITH EVEN SOME TRIPLE DIGITS POSSIBLE OVER SOME AREAS THIS WEEKEND/EARLY NEXT WEEK. THE MEDIUM RANGE PROGS DO BEGIN TO SLOWLY NUDGE THE RIDGE E INTO THE SE STATES BY TUESDAY/WEDNESDAY...WITH WEAKNESSES RIDING W BENEATH THE RIDGE ACROSS S LA/SRN MS AS EARLY AS MONDAY. THUS...ISOLATED CONVECTION WILL BE POSSIBLE OVER NCNTRL LA MONDAY AFTERNOON...BEFORE SPREADING FARTHER WNW TO ENCOMPASS MUCH OF THE REGION BY THE END OF THE EXTENDED. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 95 75 96 76 97 / 10 10 10 10 10 MLU 95 73 96 74 97 / 20 20 10 10 10 DEQ 94 71 94 71 95 / 20 20 0 0 0 TXK 94 74 96 74 96 / 20 20 0 0 0 ELD 95 72 96 74 97 / 20 20 0 0 0 TYR 95 75 96 76 97 / 10 20 10 10 10 GGG 95 74 96 75 97 / 10 10 10 10 10 LFK 96 75 96 76 97 / 20 20 20 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 06
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EDT TUE AUG 19 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 422 PM EDT TUE AUG 19 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM WRN LAKE SUPERIOR INTO W UPPER MI. A SHORTWAVE NEAR THE LOW CENTER SUPPORTED AN AREA OF SHOWERS...SOME LOCALLY HEAVY...THROUGH CNTRL UPPER MI. WITH THE SLOW FORWARD MOVEMENT...PWAT AROUND 1.5 INCHES...AND EFFICIENT WARM RAIN PROCESSES...NEARLY 2.0 INCHES OF RAIN FELL AT THE NWS OFFICE BTWN 1915Z-1945Z. AN FLS WAS ISSUED TO HIGHLIGHT THREAT FOR MINOR FLOODING WITH SMALL STREAMS AND LOW-LYING AREAS. AT THE SFC...LOW PRES WAS LOCATED OVER NW UPPER MI. EXPECT THE VERTICALLY STACKED LOW TO ONLY SLOWLY WOBBLE TO THE EAST TO CNTRL/EAST UPPER MI BY 12Z/WED AND TO NEAR THE STRAITS BY 00Z/THU. THERE WILL BE A CONTINUED THREAT FOR SOME LOCALLY HEAVY RAIN WITH THE SHRTWV MOVING THROUGH CNTRL UPPER MI THIS EVENING. ONLY ISOLD TSRA ARE EXPECTED...GIVEN AFTERNOON TRENDS AND MUCAPE BLO 1K J/KG. OTHERWISE...HIGH RES MODELS AND UPSTREAM RADAR TRENDS SUGGEST RAIN WILL BECOME MORE SCATTERED THIS EVENING AND DIMINISH FURTHER OVERNIGHT. WITH ABUNDANT DEEP MOISTURE REMAINING OVER THE REGION THROUGH WED MORNING...SOME SCT LIGHT SHOWERS OR DRIZZLE WILL REMAIN POSSIBLE THROUGH THE MORNING...ESPECIALLY OVER THE N CNTRL AND EAST EVEN WITH WEAK FORCING NEAR THE LOW. HOWEVER...ANY ADDITIONAL RAINFALL AMOUNTS SHOULD BE LIGHT...LESS THAN A TENTH OF AN INCH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 402 PM EDT TUE AUG 19 2014 THE UPPER LEVEL WAVE AND ASSOCIATED WEAK LOW PRESSURE SYSTEM THAT ARE CURRENTLY OVER THE AREA WILL CONTINUE TO INFLUENCE THE UPPER GREAT LAKES REGION INTO WEDNESDAY BEFORE PULLING OUT ON WEDNESDAY NIGHT. AS THIS WAVE PULLS OUT...SHOULD SEE A DRY PERIOD OVER MUCH OF THE U.P. FOR WEDNESDAY NIGHT INTO THURSDAY MORNING (ALTHOUGH THERE COULD BE SOME LINGERING SHOWERS OVER THE NORTHEAST ON WEDNESDAY EVENING) BEFORE THE NEXT WAVE ARRIVES THURSDAY AFTERNOON AND REMAINS INTO FRIDAY. THE DRY PERIOD WILL BE AIDED BY THE WEAK RIDGING ALOFT THAT WILL MOVE INTO THE UPPER GREAT LAKES REGION AND ATTEMPT TO BUILD INTO THE GREAT LAKES REGION THROUGH THE WEEKEND. AS THAT RIDGING OCCURS...AN UPPER TROUGH WILL ESTABLISH ITSELF OVER THE NORTHERN ROCKIES AND EJECT OUT A COUPLE PIECES OF ENERGY THROUGH THE REST OF THE EXTENDED PERIOD. THE FIRST WAVE WILL MOVE INTO THE NORTHERN PLAINS ON WEDNESDAY AND THEN SHIFT NORTHEAST ACROSS THE MINNESOTA ARROWHEAD THURSDAY EVENING AND INTO ONTARIO ON FRIDAY. THERE ARE STILL SOME MODEL DIFFERENCES WITH HOW PROGRESSIVE THIS SHORTWAVE AND ASSOCIATED WEAK LOW (AND WARM FRONT) ARE...AND IT IS LARGELY TIED INTO THE STRENGTH OF THE SHORTWAVE. AT THIS POINT...THE 12Z GFS APPEARS TO BE THE OUTLIER (KEEPS THE WARM FRONT SOUTH OF THE CWA DUE TO WEAKER SHORTWAVE UNTIL THE NEXT WAVE ARRIVES ON SATURDAY) WHILE THE 00Z ECMWF AND ITS ENSEMBLE MEMBERS...ALONG WITH THE 12Z GEM/NAM...BRING THE WARM FRONT INTO THE AREA LATE THURSDAY AFTERNOON AND PUSHING NORTHEAST OF THE AREA ON FRIDAY NIGHT INTO SATURDAY. THINK THE NON GFS CONSENSUS IS THE WAY TO GO AT THIS POINT AND FOLLOWS THE GENERAL IDEA FROM THE PREVIOUS SHIFT. THEREFORE...WILL INCREASE PRECIP CHANCES FROM SOUTHWEST TO NORTHEAST THURSDAY AFTERNOON INTO THURSDAY NIGHT AND THEN KEEP CHANCE POPS INTO THE FIRST PART OF THE WEEKEND. WILL NEED TO KEEP AN EYE ON CONVECTION FIRING IN EAST CENTRAL MINNESOTA AND NORTHWEST WISCONSIN THURSDAY AFTERNOON ALONG THE WARM FRONT AND LOW LEVEL MOISTURE TRANSPORT MAXIMUM IS LOCATED. COULD SEE SOME STRONG TO POTENTIAL SEVERE STORMS IN THAT AREA...WHICH BASED OFF STORM MOTION VECTORS WOULD TRY TO LIFT THEM EAST-NORTHEAST ALONG WITH THE FRONT WHILE BUILDING TO THE SOUTHEAST. FAR WESTERN UPPER MICHIGAN WOULD HAVE THE BEST OPPORTUNITY FOR SEEING THESE STRONGER STORMS HEADING INTO THE EVENING HOURS. ONCE THAT WAVE DECAYS AND SLIDES NORTHEAST OF THE CWA...PRECIPITATION CHANCES WILL DEPEND ON OTHER WAVES EJECTING OUT OF THE UPPER TROUGH OVER THE NORTHERN ROCKIES. RIDGE AXIS WILL BE RIGHT OVER THE U.P. THROUGH SUNDAY AND THEN SHIFT EAST FOR THE BEGINNING OF NEXT WEEK AS THE UPPER TROUGH GRADUALLY SHIFTS EAST. WITH THAT RIDGE AXIS...IT APPEARS THAT SUNDAY WILL BE THE BEST OPPORTUNITY FOR DRIER WEATHER BEFORE THE NEXT WAVE SLIDES NORTHEAST OVER THE WESTERN HALF OF THE CWA SUNDAY NIGHT INTO MONDAY MORNING. EXPECT IT TO BE FAIRLY MUGGY OVER THE AREA FRIDAY INTO THE WEEKEND....ESPECIALLY WHEN COMPARED TO WHAT HAS BEEN SEEN IN THIS REGION FOR MUCH OF THE SUMMER. AFTER THE NORMAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES VALUES THURSDAY THROUGH SUNDAY...THEY ARE EXPECTED TO FALL BACK BELOW NORMAL FOR MONDAY AND TUESDAY BEHIND THE COLD FRONT ASSOCIATED WITH THE WAVE THAT MOVES THROUGH ON SUNDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 203 PM EDT TUE AUG 19 2014 WITH A LOW PRESSURE SYSTEM REMAINING IN THE AREA WITH ABUNDANT LOW LEVEL MOISTURE...LIFR TO VLIFR CONDITIONS SHOULD PREVAIL AT ALL SITES THIS PERIOD WITH NRLY UPSLOPE FLOW AND OCCASIONAL LIGHT SHOWERS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 422 PM EDT TUE AUG 19 2014 SOME FOG IS EXPECTED TO PERSIST OVER THE CNTRL AND ERN LAKE TONIGHT GIVEN ABUNDANT LOW LEVEL MOISTURE AND LIGHT WINDS. EXPECT WINDS UNDER 20 KTS THROUGH SATURDAY AS A RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE RELATIVELY COLD WATERS OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
521 PM CDT TUE AUG 19 2014 .UPDATE... ISSUED AT 521 PM CDT TUE AUG 19 2014 UPDATED TO INCLUDE A SLIGHT CHANCE FOR THUNDERSTORMS FROM SWRN NEBR INTO CENTRAL NEBRASKA AS THIS EVENING PROGRESSES. LATEST REGIONAL RADAR MOSAIC SHOWS SCATTERED THUNDERSTORMS FROM NEAR SCOTTSBLUFF THROUGH FORT MORGAN AND LAST CHANCE COLORADO. THE LATEST HRRR AND RAP13 INDICATE THIS TO PUSH NORTHEAST AND INCREASE IN COVERAGE INTO WRN NEBR THIS EVENING. RECENT ISOLATED DEVELOPMENT NOW IN SHERIDAN AND CHERRY COUNTY ATTM. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 337 PM CDT TUE AUG 19 2014 SHORTWAVE RIDGING ALOFT CURRENTLY RESIDES OVER THE AREA...WITH VERY LITTLE IN THE WAY OF CLOUD COVER EXCEPT FOR SOME HIGH CIRRUS CLOUDS. SHORT TERM HRRR MODEL SUGGESTS THUNDERSTORMS WILL DEVELOP OVER THE HIGHER TERRAIN TO THE WEST LATE THIS AFTERNOON...AND THEN DRIFT EAST INTO WESTERN NEBRASKA THIS EVENING. LATEST VISIBLE SATELLITE TRENDS CONFIRMS THIS THINKING...WITH QUITE A BIT IN THE WAY OF TOWERING CUMULUS FROM CHEYENNE DOWN THROUGH THE DENVER METRO. SOUTHERLY LOW LEVEL JET WILL INCREASE TO AROUND 35 KTS THIS EVENING...WHICH MAY HELP SUPPORT STORMS AS THEY TRACK EAST. NOT EXPECTING COVERAGE TO BE WIDESPREAD...AND DUE TO THE RIDGING ALOFT...NOT REAL CONFIDENT ON HOW FAR EAST STORMS WILL MAKE IT. LATER TONIGHT...DECENT MID LEVEL INSTABILITY DEVELOPS ACROSS NORTH CENTRAL INTO NORTHEAST NEBRASKA...AND EXPECT AT LEAST SCATTERED COVERAGE OF ELEVATED THUNDERSTORMS TO DEVELOP WITHIN AREA OF ISENTROPIC ASCENT. A SURFACE TROUGH WILL EXTEND FROM NORTHEAST TO SOUTHWEST WEDNESDAY AFTERNOON...AND SHOULD BE THE FOCUS FOR SCATTERED LATE AFTERNOON THUNDERSTORMS. THE NAM MODEL IS THE FARTHEST EAST WITH THE TROUGH...WHILE THE NMM...ARW AND GEM REGIONAL HOLD THE TROUGH BACK FROM ROUGHLY AINSWORTH TO IMPERIAL. DECENT INSTABILITY DEVELOPS BY AFTERNOON ALONG AND EAST OF THE TROUGH...WITH SURFACE BASED CAPES APPROACHING 4000 J/KG. A BELT OF STRONGER MID LEVEL WINDS WILL ALSO BE PRESENT BY AFTERNOON ON THE SOUTHERN FLANK OF A SHORTWAVE CROSSING THE NORTHERN PLAINS. THE SYNOPTIC SET UP APPEARS SIMILAR TO THE SUNDAY SEVERE EVENT...AND AGREE WITH THE STORM PREDICTION CENTER SLIGHT RISK FOR SEVERE STORMS EAST OF HIGHWAY 83. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 337 PM CDT TUE AUG 19 2014 THE WEAK FRONT WILL CROSS CENTRAL NEBRASKA WEDNESDAY NIGHT AND GENERATE A BAND OF THUNDERSTORMS...ESPECIALLY IN CENTRAL AND NORTH CENTRAL NEBRASKA. MODEL OUTPUT STATISTICS INDICATE PROBABILITY/ COVERAGE OF 20-30 PERCENT IN THE SANDHILLS AND 30-40 PERCENT IN CENTRAL AND NORTH CENTRAL NEBRASKA. THAT SEEMS REASONABLE. SURFACE BASED CAPE IN CENTRAL AND NORTH CENTRAL NEBRASKA IS PRETTY HIGH AT 3500-4000J/KG WITH BULK SHEAR (0-6KM) AROUND 30KT. WITH STORM MOTION 240-260 AT 15-25KT...STORM RELATIVE HELICITY IS EXPECTED TO BE 110-200. SEVERE STORMS ARE POSSIBLE INTO THE EVENING...THOUGH WE WILL NOT INCLUDE THE MENTION IN THE FORECAST FOR WEDNESDAY NIGHT. A BOUNDARY LIFTING NORTH INTO SOUTHERN NEBRASKA WILL BRING THE POSSIBILITY OF THUNDERSTORMS TO SOUTH CENTRAL AND SOUTHWEST NEBRASKA THURSDAY NIGHT. AS THE BOUNDARY MAKES ITS WAY A LITTLE FARTHER NORTH FRIDAY...THERE IS A POSSIBILITY OF THUNDERSTORMS IN CENTRAL AND NORTHERN NEBRASKA. FINALLY...SATURDAY NIGHT AND SUNDAY...A COOL FRONT COMES ACROSS NEBRASKA AND THE PATTERN IS NOT AS FAVORABLE FOR STRONG CONVECTION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1239 PM CDT TUE AUG 19 2014 VFR CONDITIONS WILL PREVAIL ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THROUGH TONIGHT. ISOLATED THUNDERSTORMS MAY MOVE EASTWARD INTO FAR WESTERN NEBRASKA THIS EVENING...AND SOME ISOLATED DEVELOPMENT IS ALSO POSSIBLE LATE TONIGHT ACROSS NORTH CENTRAL NEBRASKA. DUE TO THE ISOLATED NATURE...NO MENTION IS WARRANTED IN THE OFFICIAL TAF FORECAST. WINDS WILL GENERALLY BE SOUTHEAST AROUND 10 KTS THROUGH TONIGHT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ROBERG SHORT TERM...TAYLOR LONG TERM...SPRINGER AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
338 PM CDT TUE AUG 19 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 337 PM CDT TUE AUG 19 2014 SHORTWAVE RIDGING ALOFT CURRENTLY RESIDES OVER THE AREA...WITH VERY LITTLE IN THE WAY OF CLOUD COVER EXCEPT FOR SOME HIGH CIRRUS CLOUDS. SHORT TERM HRRR MODEL SUGGESTS THUNDERSTORMS WILL DEVELOP OVER THE HIGHER TERRAIN TO THE WEST LATE THIS AFTERNOON...AND THEN DRIFT EAST INTO WESTERN NEBRASKA THIS EVENING. LATEST VISIBLE SATELLITE TRENDS CONFIRMS THIS THINKING...WITH QUITE A BIT IN THE WAY OF TOWERING CUMULUS FROM CHEYENNE DOWN THROUGH THE DENVER METRO. SOUTHERLY LOW LEVEL JET WILL INCREASE TO AROUND 35 KTS THIS EVENING...WHICH MAY HELP SUPPORT STORMS AS THEY TRACK EAST. NOT EXPECTING COVERAGE TO BE WIDESPREAD...AND DUE TO THE RIDGING ALOFT...NOT REAL CONFIDENT ON HOW FAR EAST STORMS WILL MAKE IT. LATER TONIGHT...DECENT MID LEVEL INSTABILITY DEVELOPS ACROSS NORTH CENTRAL INTO NORTHEAST NEBRASKA...AND EXPECT AT LEAST SCATTERED COVERAGE OF ELEVATED THUNDERSTORMS TO DEVELOP WITHIN AREA OF ISENTROPIC ASCENT. A SURFACE TROUGH WILL EXTEND FROM NORTHEAST TO SOUTHWEST WEDNESDAY AFTERNOON...AND SHOULD BE THE FOCUS FOR SCATTERED LATE AFTERNOON THUNDERSTORMS. THE NAM MODEL IS THE FARTHEST EAST WITH THE TROUGH...WHILE THE NMM...ARW AND GEM REGIONAL HOLD THE TROUGH BACK FROM ROUGHLY AINSWORTH TO IMPERIAL. DECENT INSTABILITY DEVELOPS BY AFTERNOON ALONG AND EAST OF THE TROUGH...WITH SURFACE BASED CAPES APPROACHING 4000 J/KG. A BELT OF STRONGER MID LEVEL WINDS WILL ALSO BE PRESENT BY AFTERNOON ON THE SOUTHERN FLANK OF A SHORTWAVE CROSSING THE NORTHERN PLAINS. THE SYNOPTIC SET UP APPEARS SIMILAR TO THE SUNDAY SEVERE EVENT...AND AGREE WITH THE STORM PREDICTION CENTER SLIGHT RISK FOR SEVERE STORMS EAST OF HIGHWAY 83. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 337 PM CDT TUE AUG 19 2014 THE WEAK FRONT WILL CROSS CENTRAL NEBRASKA WEDNESDAY NIGHT AND GENERATE A BAND OF THUNDERSTORMS...ESPECIALLY IN CENTRAL AND NORTH CENTRAL NEBRASKA. MODEL OUTPUT STATISTICS INDICATE PROBABILITY/ COVERAGE OF 20-30 PERCENT IN THE SANDHILLS AND 30-40 PERCENT IN CENTRAL AND NORTH CENTRAL NEBRASKA. THAT SEEMS REASONABLE. SURFACE BASED CAPE IN CENTRAL AND NORTH CENTRAL NEBRASKA IS PRETTY HIGH AT 3500-4000J/KG WITH BULK SHEAR (0-6KM) AROUND 30KT. WITH STORM MOTION 240-260 AT 15-25KT...STORM RELATIVE HELICITY IS EXPECTED TO BE 110-200. SEVERE STORMS ARE POSSIBLE INTO THE EVENING...THOUGH WE WILL NOT INCLUDE THE MENTION IN THE FORECAST FOR WEDNESDAY NIGHT. A BOUNDARY LIFTING NORTH INTO SOUTHERN NEBRASKA WILL BRING THE POSSIBILITY OF THUNDERSTORMS TO SOUTH CENTRAL AND SOUTHWEST NEBRASKA THURSDAY NIGHT. AS THE BOUNDARY MAKES ITS WAY A LITTLE FARTHER NORTH FRIDAY...THERE IS A POSSIBILITY OF THUNDERSTORMS IN CENTRAL AND NORTHERN NEBRASKA. FINALLY...SATURDAY NIGHT AND SUNDAY...A COOL FRONT COMES ACROSS NEBRASKA AND THE PATTERN IS NOT AS FAVORABLE FOR STRONG CONVECTION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1239 PM CDT TUE AUG 19 2014 VFR CONDITIONS WILL PREVAIL ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THROUGH TONIGHT. ISOLATED THUNDERSTORMS MAY MOVE EASTWARD INTO FAR WESTERN NEBRASKA THIS EVENING...AND SOME ISOLATED DEVELOPMENT IS ALSO POSSIBLE LATE TONIGHT ACROSS NORTH CENTRAL NEBRASKA. DUE TO THE ISOLATED NATURE...NO MENTION IS WARRANTED IN THE OFFICIAL TAF FORECAST. WINDS WILL GENERALLY BE SOUTHEAST AROUND 10 KTS THROUGH TONIGHT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...TAYLOR LONG TERM...SPRINGER AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
359 PM EDT TUE AUG 19 2014 .SYNOPSIS... LOW PRESSURE OVER LAKE MICHIGAN WILL SLOWLY MOVE TO THE EASTERN GREAT LAKES THROUGH THURSDAY...PUSHING A WEAK COLD FRONT SOUTH ACROSS THE AREA. HIGH PRESSURE WILL BUILD OVER LAKE ERIE BEHIND THIS SYSTEM THURSDAY NIGHT...SHIFTING TO THE EASTERN GREAT LAKES ON FRIDAY. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON FRIDAY AND SATURDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... SHOWERS AND THUNDERSTORMS CONTINUE TO FILL IN ACROSS SW LOWER MICHIGAN INTO INDIANA AHEAD OF A LOW PRESSURE SYSTEM LOCATED OVER LAKE MICHIGAN. THIS REGION IS ALSO LOCATED AHEAD OF AN UPPER LEVEL LOW SPINNING OVER THE WESTERN GREAT LAKES. THE SOUTHERN PORTION OF THIS COMPLEX IS THE REMNANTS OF A LONG LIVED MCS THAT TRACKED OUT OF MISSOURI THIS MORNING AND IS NOW MERGING WITH THE CONVECTION DEVELOPING ALONG THE FRONT. STORM MOTION THIS AFTERNOON IS TO THE NORTHEAST...ALTHOUGH THE CLUSTER OVER MICHIGAN IS SHOWING A TENDANCY TO SLOWLY SINK SOUTH WITH TIME. IT LOOKS LIKE THE CLUSTER MOVING OUT OF INDIANA WILL APPROACH THE TOLEDO AREA TOWARDS 6 PM. A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR AREAS JUST WEST AND NORTH OF TOLEDO AND THE WATCH MAY NEED TO BE EXPANDED IN NW OHIO IF THUNDERSTORMS CAN MAINTAIN STRENGTH. THUS FAR THE GREATEST THREAT HAS BEEN HEAVY RAIN WHERE STORMS HAVE BEEN TRAINING IN MICHIGAN WITH NO REPORTS OF SEVERE WEATHER. AS OF 330 PM...NO WARNINGS HAVE BEEN ISSUED WITH THE CONVECTION IN NRN INDIANA WHICH IS STARTING TO OUTPACE THE FRONT. THERE IS SUFFICIENT INSTABILITY WITH ML CAPES AROUND 1500 J/KG FOR STRONG TO SEVERE STORMS BUT SHEAR IS LACKING. CORRIDOR OF DEEPER MOISTURE WILL CONTINUE TO MOVE NORTHEAST AHEAD OF THE SURACE AND UPPER LEVEL LOW OVERNIGHT AND SHOWERS AND THUNDERSTORMS ARE EXPECTED MOST AREAS. STORMS SHOULD WEAKEN AS WE LOSE DIURNAL HEATING OVERNIGHT AND MAY BE MAINLY SHOWERS EAST OF I-77 BY MORNING. DEWPOINTS/HUMIDITY WILL CONTINUE TO INCREASE OVERNIGHT WHICH WILL KEEP TEMPERATURES MILD TONIGHT. LOWS ARE FORECAST TO DROP INTO THE MID 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... NEARLY VERTICALLY STACKED UPPER LEVEL AND SURFACE LOW WILL BE OVER THE CENTRAL GREAT LAKES ON WEDNESDAY. A MOIST AND UNSTABLE AIRMASS WILL RESIDE WITHIN THE AREA OF SOUTHERLY FLOW AHEAD OF THE SURFACE LOW ACROSS MAINLY NE OHIO AND NW PA. CAPES ARE EXPECTED TO INCREASE TO AROUND 2500 J/KG WITH SEVERAL MECHANISMS FOR CONVECTIVE INITIATION DURING THE AFTERNOON. STORMS WILL FIRE DURING THE AFTERNOON AS THE LOW SLOWLY MOVES EASTWARD. HIGHER RESOLUTION MODELS ALSO SHOW SOME CONVERGENCE DOWNWIND OF LAKE ERIE THAT WILL SET UP SOUTH OF I-90. LARGE SCALE FORCING WILL ALSO INCREASE DURING THE LATE AFTERNOON AS A 35 KNOT MID-LEVEL JET STREAK MOVES THROUGH THE NORTHWESTERLY FLOW ON THE BACK SIDE OF THE TROUGH. ALL OF THIS COMBINES TO MAKE THUNDERSTORMS LIKELY ON THURSDAY ACROSS AT LEAST THE EASTERN HALF OF THE FORECAST AREA. LESS CERTAIN IS IF ANYTHING CAN FIRE ACROSS NW OHIO AHEAD OF THE JET STREAK WHICH CAN NOT BE ENTIRELY RULED OUT SO WILL LEAVE A LOW POP IN THE NW OHIO. WHATEVER BREAKS EXIST IN THE CLOUDS TO START THE DAY IN NE OHIO/NW PA WILL FILL IN QUICKLY AS DIURNAL HEATING INCREASES...WHILE A GOOD DEAL OF SUN IS EXPECTED IN THE DRIER AIR IN NW OHIO. HIGHS WILL RANGE FROM 77-85 AND WILL BE HIGHEST IN THE WEST WHERE THEY WILL RECEIVE MORE SUN. WEDNESDAY NIGHT WILL BE MOSTLY DRY AS WEAK COLD FRONT PUSHES SOUTH WITH NEGATIVE THETA-E ADVECTION THROUGH THE COLUMN. WEAK HIGH PRESSURE ALSO BUILDS IN BEHIND THE DEPARTING SURFACE LOW WHICH SHOULD REDUCE CHANCES FOR PRECIPITATION DOWNWIND OF LAKE ERIE IN NE OH/NW PA ON THURSDAY. FARTHER SOUTH...SCATTERED THUNDERSTORMS ARE EXPECTED TO FIRE ALONG STALLED BOUNDARY ON THURSDAY. THURSDAY NIGHT COULD ALSO BE ACTIVE ACROSS THE SW HALF OF THE FORECAST AREA AS ENERGY MOVES AROUND THE BUILDING RIDGE THURSDAY NIGHT. THIS WILL BE FOLLOWED BY A WARM FRONT STARTING TO LIFT BACK NORTH ON FRIDAY. THIS WILL BE THE BEGINNING OF THE WARMING TREND FOR THE WEEKEND...WITH HIGHS REACHING THE MID TO UPPER 80S IN THE WEST ON FRIDAY. && .LONG TERM /SATURDAY THROUGH TUESDAY/... THE LONG TERM BEGINS ON SATURDAY WITH BOTH THE GFS AND ECMWF SHOWING AN UPPER LEVEL HIGH CENTERED OVER THE SOUTHEASTERN STATES. A RIDGE WILL EXTEND NORTH INTO THE CENTRAL LAKES. NOT MUCH CHANGES THROUGH SUNDAY INTO MONDAY EXCEPT THAT LOW PRESSURE MOVING THROUGH SOUTHERN CANADA WILL TILT THE AXIS OF THE RIDGE EAST A BIT HOWEVER IT SHOULD STILL REMAIN WEST OF THE AREA. TUESDAY THE LOW MOVES TO NORTHERN ONTARIO FLATTENING THE RIDGE ACROSS THE LAKES. GIVEN THE RIDGE POSITION...WOULD EXPECT THAT ANY CONVECTION THAT GOES OVER THE TOP OF THE RIDGE WILL DESCEND ON THE REGION FROM THE NORTH. FOR NOW THOUGH IT WOULD BE FAIRLY DIFFICULT TO ANTICIPATE TIMING OTHER THAT A SMALL CHANCE POP FOR AFTERNOON AND EARLY EVENING CONVECTION. WILL HAVE A SLIGHT CHANCE POP IN FOR THE OVERNIGHT AND EARLY MORNING PERIODS. ALSO...GUIDANCE SUGGESTS MORE CLOUD COVER THEN SEEMS REASONABLE GIVEN THE RIDGE SO LOWERED CLOUD PERCENTAGES TO GET PARTLY CLOUDY THROUGH MOST OF THE PERIOD. TEMPS AT OR ABOVE NORMAL. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... LOW PRESSURE MOVING INTO THE CENTRAL LAKES THIS AFTERNOON WITH CONVECTION NOW FROM SRN/CENTRAL LWR MI ACRS SRN LAKE MI INTO NRN INDIANA. ACTIVITY TIMES INTO NWRN OHIO 22Z-24Z. USING TIMING FROM THE HRRR AS WELL AS SPC MODELS...CONVECTION TIMES INTO KCLE AROUND 00Z AND KERI/KCAK/YNG 02Z-04Z. OVERNIGHT AFTER THE CONVECTION EXPECT CONDITIONS WILL DROP TO MVFR/IFR IN LOWER CIGS AND MIST/FOG GIVEN THE ADDED LOW LEVEL MOISTURE AS WELL AS MOISTURE ASSOCIATED WITH THE LOW AFFECTING THE REGION. OUTLOOK...NON VFR POSSIBLE IN SHOWERS/THUNDERSTORMS THROUGH FRIDAY. && .MARINE... LOW PRESSURE OVER THE GREAT LAKES WILL CONTINUE THROUGH TONIGHT AND TUESDAY INTO MID WEEK...EVENTUALLY REACHING WESTERN NEW YORK BY THURSDAY MORNING. FLOW AROUND THE LOW IS NOT PARTICULARLY STRONG SO AM EXPECTING VARIABLE BUT GENERALLY LIGHT WINDS THROUGH THE PERIOD RESULTING IN WAVES OF 2 FEET OR LESS ON THE LAKE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KEC NEAR TERM...KEC SHORT TERM...KEC LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
151 PM EDT TUE AUG 19 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD INTO NORTHERN OHIO TODAY AS LOW PRESSURE TRACKS INTO NORTHERN MICHIGAN TONIGHT. AS THE LOW PROGRESSES SLOWLY EASTWARD INTO THURSDAY IT WILL DRAG A COLD FRONT ACROSS THE REGION. THIS FRONTAL BOUNDARY WILL REMAIN A FACTOR INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DEWPOINTS ARE INCREASING INTO THE UPPER 60S ACROSS WESTERN OHIO. SHOWERS AND THUNDERSTORMS ARE FILLING IN ALONG THE WARM FRONT IN WESTERN MICHIGAN...EXTENDING WESTWARD ACROSS LAKE MICHIGAN TOWARDS THE MCS IN ILLINOIS. IT WILL TAKE SEVERAL HOURS YET FOR THIS ACTIVITY TO REACH NORTHWEST OHIO. SLOWED DOWN THE CHANCE OF THUNDERSTORMS A LITTLE BIT MORE FOR LATER TODAY AND REMOVED THE SLIGHT CHANCE OF THUNDERSTORMS FROM NORTHEAST OHIO. INSTABILITY IS INCREASING ACROSS INDIANA WITH ML CAPE VALUES NEAR 2000 J/KG. AT THIS TIME THERE STILL APPEARS TO BE A SEVERE WEATHER THREAT FOR NW OHIO INTO THIS EVENING AS THIS ACTIVITY APPROACHES. THE CIRRUS SHIELD IS STARTING TO OUTPACE THE CONVECTION THOUGH SO WE WILL HAVE TO SEE WHAT EFFECT THAT HAS ON INSTABILITY LATER TODAY. PREVIOUS DISCUSSION...WE WILL CONTINUE TO WATCH THE UPSTREAM CLUSTER OF THUNDERSTORMS MOVING INTO ILLINOIS. THIS ACTIVITY IS ONGOING IN AN AREA OF BETTER INSTABILITY WITH A WEAK JET STREAK IN THE MID-LEVEL FLOW NEAR 500MB. MID-LEVEL LAPSE RATES ARE FAIRLY STEEP ACROSS ILLINOIS AHEAD OF THIS FEATURE SO COULD SEE THIS ACTIVITY HOLD TOGETHER AND STRENGTHEN AS IT CONTINUES EASTWARD. CONVECTION WILL LIKELY ALSO DEVELOP ACROSS SW MICHIGAN/INDIANA IN THE VICINITY OF THE OUTFLOW BOUNDARY FROM THIS MORNING AND IT WILL BE INTERESTING TO SEE HOW THIS INTERACTS WITH THE LARGER COMPLEX TO THE WEST. CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS NW OHIO WILL INCREASE LATE THIS AFTERNOON...LIKELY AFTER 4 PM...THEN SPREAD EASTWARD TONIGHT. NW OHIO REMAINS IN THE SLIGHT RISK FOR SEVERE STORMS AS INSTABILITY AND LARGE SCALE ASCENT INCREASES AHEAD OF THE UPPER LOW APPROACHING LAKE MICHIGAN. ORIGINAL DISCUSSION... A WARM FRONT WILL SLOWLY LIFT NORTHWARD ACROSS OHIO TODAY. LIFT OVER THIS BOUNDARY...AFTERNOON HEATING AND INCREASING SHEAR ASSOCIATED WITH A 5H 40 KNOT JET WILL HELP TO DEVELOP THUNDERSTORMS OVER SOUTHERN MICHIGAN SOUTHWARD INTO INDIANA THIS AFTERNOON. A FEW OF THESE THUNDERSTORMS WILL BE CAPABLE OF PRODUCING STRONG DAMAGING WINDS AND LARGE HAIL AS THEY MOVE TOWARD NW OHIO LATE THIS AFTERNOON INTO THE EVENING. EASTERN AREAS WILL TAKE MOST OF THE DAY TO MOISTEN UP SO THE THREAT OF THUNDERSTORMS IS MINIMAL. IT WILL BE ANOTHER WARM DAY WITH HIGHS SIMILAR TO YESTERDAYS. ACTUALLY IT WILL PROBABLY BE A DEGREE OR TWO WARMER AT MOST LOCATIONS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THERE WILL BE A THREAT OF SEVERE THUNDERSTORMS UNTIL SHORTLY AFTER SUNSET THIS EVENING. BEYOND THAT IT APPEARS THERE WILL BE AN AREA OF SHOWERS AND THUNDERSTORMS THAT MOVE FROM WEST TO EAST ACROSS THE REGION WITH A WEAKENING COLD FRONT. IT WILL LIKELY TAKE UNTIL AFTER MIDNIGHT FOR THE RAIN TO REACH EXTREME NE OHIO INTO NW PA. THIS WEAK FRONT WILL END UP BEING A FACTOR IN THE WEATHER THROUGH THE SECOND HALF OF THE WEEK. IT IS DIFFICULT TO SAY WHERE THIS BOUNDARY WILL BE LOCATED EACH DAY WITH IT POTENTIALLY BEING PUSHED SOUTH OF THE COUNTY WARNING AREA BY THURSDAY. SINCE THERE IS SO MUCH UNCERTAINTY WE WILL KEEP LOW CHANCES GOING IN THE FORECAST AT THIS TIME. HOWEVER WITH INCREASING HEIGHTS OVER THE REGION WE MAY BE ABLE TO SHUT THE RAIN CHANCES OFF FASTER THAN WHAT THE CURRENT FORECAST INDICATES. IT WILL REMAIN WARM THROUGH THE SHORT TERM WITH HIGHS REMAINING SLIGHTLY ABOVE SEASONAL AVERAGES. && .LONG TERM /SATURDAY THROUGH MONDAY/... UPPER LEVEL HIGH PRESSURE WILL ENCOMPASS THE ENTIRE EASTERN UNITED STATES BY SATURDAY AND BUILD GRADUALLY EAST THROUGH THE PERIOD. HOWEVER...ATMOSPHERE IS A BIT ACTIVE AS SMALL WEAK SHORTWAVE TROUGHS ROTATE OVER THE NORTH SIDE OF THE HIGH INTO THE FORECAST AREA THROUGH MUCH OF THE EXTENDED PERIOD. EXPECTING SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS JUST ABOUT EACH DAY. THIS IS ALSO IN RESPONSE TO SOME WARM AIR ADVECTION TAKING PLACE AND THE CLOSE PROXIMITY OF A STATIONARY FRONT. SO...THE TEMPERATURES AND PRECIPITATION THREAT IS ALL DEPENDENT ON WHERE THE STATIONARY FRONT IS AT...AT ANY GIVEN MOMENT. SOME PLACES IN THE WEST COULD HIT 90 DEGREES FOR HIGHS ON SATURDAY WHILE COOLER TEMPERATURES OCCUR THE FURTHER EAST ONE GOES. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... LOW PRESSURE MOVING INTO THE CENTRAL LAKES THIS AFTERNOON WITH CONVECTION NOW FROM SRN/CENTRAL LWR MI ACRS SRN LAKE MI INTO NRN INDIANA. ACTIVITY TIMES INTO NWRN OHIO 22Z-24Z. USING TIMING FROM THE HRRR AS WELL AS SPC MODELS...CONVECTION TIMES INTO KCLE AROUND 00Z AND KERI/KCAK/YNG 02Z-04Z. OVERNIGHT AFTER THE CONVECTION EXPECT CONDITIONS WILL DROP TO MVFR/IFR IN LOWER CIGS AND MIST/FOG GIVEN THE ADDED LOW LEVEL MOISTURE AS WELL AS MOISTURE ASSOCIATED WITH THE LOW AFFECTING THE REGION. OUTLOOK...NON VFR POSSIBLE IN SHOWERS/THUNDERSTORMS THROUGH FRIDAY. && .MARINE... NOT MUCH TO TALK ABOUT ON THE LAKE OVER THE NEXT 5 DAYS. WINDS ARE EXPECTED TO BE RELATIVELY LIGHT AND THEREFORE TRANSLATE TO WAVES OF GENERALLY ONE FOOT OR LESS THROUGH THE PERIOD. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...MULLEN NEAR TERM...KEC/MULLEN SHORT TERM...MULLEN LONG TERM...LOMBARDY AVIATION...TK MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1225 PM EDT TUE AUG 19 2014 .SYNOPSIS... A VERY WARM...HUMID AND ACTIVE WEATHER PATTERN CONTINUES. AN UPPER LEVEL DISTURBANCE CROSSES TONIGHT. A WARM FRONT SETS UP TO THE WEST OF THE AREA WEDNESDAY NIGHT...AND THEN MOVES INTO THE AREA ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... SENT A QUICK UPDATE TO ADJUST POPS PER LATEST RADAR IMAGES SHOWING WEAK CONVECTION ACROSS THE SOUTH AND WESTERN SLOPES OF WV AROUND NOON. EXPECT THIS ACTIVITY TO INCREASE IN COVERAGE AND INTENSITY PER HIGH RESOLUTION MODELS INDICATING INCREASE IN SFC BASED CAPE FROM 1600-2000 J/KG BY THE RAP AND NAM MODELS. THESE VALUES LOOKS REASONABLE COMPARED WITH DEWPOINTS IN THE LOWER 70S ACROSS THE AREA. PWATS IN THE ORDER OF 1.4 INCHES...ACCORDING WITH SATELLITE DERIVED PRODUCTS...AND DIFFERENTIAL HEATING FROM BREAKS IN THE SKY WILL ALLOW CONVECTION TO STRENGTHEN INTO ISOLATED THUNDERSTORMS THIS AFTERNOON AND TONIGHT. MODELS ALSO SHOW A SHORTWAVE AT 5 BRINGING A VORTICITY MAXIMA ACROSS THE AREA BY 06Z WEDNESDAY. THIS FEATURE WILL ENHANCE CONVECTION TONIGHT. INCREASED POPS TO LIKELY WITH THIS LATEST FEATURE. HOURLY TEMPERATURES ADJUSTED AS WELL PER LATEST SFC OBS. PREVIOUS DISCUSSION BELOW... 630 AM UPDATE... FCST ON TRACK. PREV DISCN... ISOLATED SHOWERS WITH PINHEAD DOWNPOURS CONTINUE OVER SE PORTIONS OF THE FCST AREA IN THE WAKE OF AN UPPER LEVEL S/W TROUGH AND SFC LOW THAT CROSSED MON. LOW LEVEL WNW UPSLOPE FLOW AND HIGH PW VALUES ARE LIKELY HELPING TO MAINTAIN THIS ACTIVITY...WHICH SHOULD WANE A BIT FURTHER BUT PERHAPS NOT ALTOGETHER DISAPPEAR LATER THIS MORNING. OTHERWISE LOW CLOUDS WILL BE SLOW TO MIX OUT THIS MORNING...AS THE FOG SLOWLY THINS. THE AREA REMAINS IN A VERY MOIST AND HUMID AIR MASS TODAY WITH INSTABILITY LEADING TO DIURNAL CONVECTION THIS AFTERNOON. THE LACK OF FORCING SUGGESTS THERE WILL NOT BE MUCH COVERAGE...BUT THE LIGHT FLOW THROUGH H5 SPELLS SLOW MOVEMENT ON ANYTHING THAT DOES STAND UP. UPPER LEVEL S/W TROUGH CROSSES TONIGHT...ITS TIMING SLOWER COMPARED WITH PREVIOUS RUNS. ANY SEVERE POTENTIAL WITH IT WILL BE MAINLY W OF THE AREA BECAUSE OF THIS...ALTHOUGH STRONG STORMS CAN MAKE IT INTO THE MIDDLE OHIO VALLEY BEFORE SUNSET. STRATUS AND FOG WILL LIKELY FOLLOW THE SHOWERS AND THUNDERSTORMS LATE TONIGHT. MINOR CHANGES TO TEMPERATURES IN LIGHT OF LATEST BIAS CORRECTED GUIDANCE...A LITTLE WARMER TODAY WITH THE SLOWER SYSTEM...AND ANOTHER VERY WARM AND MUGGY NT TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. UPPER LOW/TROUGH MOVING EAST...WITH A MAINLY NWLY FLOW ALOFT...WITH SEVERAL UPPER DISTURBANCES MOVING INTO THE REGION. THIS...COMBINED WITH THE HUMID AIRMASS IN PLACE...WILL KEEP A MENTION OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. PW VALUES DURING THE PERIOD WILL REMAIN RATHER HIGH...GENERALLY 1.5 INCHES OR HIGHER...THUS CONTINUING THE THREAT FOR HEAVY DOWNPOURS. IN ADDITION...COULD BE STORMS ON THE STRONGER SIDE WEDNESDAY/WEDNESDAY NIGHT...PARTICULARLY SOUTHEAST OHIO AND EASTERN KY WHERE BETTER CAPE/SHEAR WILL EXIST. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... USED WPC THINKING WITH SOME TWEAKS. NORTHWEST UPPER LEVEL FLOW IS ANTICIPATED THROUGH MUCH OF THE PERIOD...WITH HIGH PRESSURE TRYING TO BUILD IN LATE. AT THE SURFACE...A NW-SE ORIENTED FRONT SHOULD BE LOCATED NEARBY THROUGH MUCH OF THE PERIOD. WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... LOW STRATUS DOMINATES EARLY THIS MORNING. IT TOOK THE LOWERING OF IT TO REALIZE DENSE FOG AT HTS AND IT LOOKED LIKE THE SAME THING WAS HAPPENING AT EKN AS 11Z APPROACHED. THE SAME MAY HAPPEN AT OTHER SITES AS WE NEAR AND CROSS THE START OF THE 1912/2012 TAF PERIOD. THE FOG WILL THIN INTO AN MVFR MIST BY MID MORNING BEFORE DISAPPEARING ALTOGETHER...BUT IT WILL TAKE MUCH OF NOT ALL OF THE MORNING FOR THE STRATUS TO LIFT THROUGH AND THEN ABOVE THE MVFR RANGE. MVFR STRATOCU MAY HANG ON INTO THE AFTERNOON IN THE MOUNTAINS. THE PROBLEM TONIGHT WILL BE THUNDERSTORMS...ALTHOUGH THIS FCST IS ALSO A BIT UNCERTAIN. THE STORMS SHOULD FIRE UP IN THE MIDDLE OHIO VALLY AS A SYSTEM APPROACHES FROM THE NW LATER TODAY. THE STORMS WILL MOVE QUICKLY SEWD THROUGH THE MIDDLE OHIO VALLEY AND THEN THE CENTRAL APPALACHIANS TONIGHT. POST RAIN STRATUS AND FOG ARE LIKELY TO FORM IN THE WAKE OF THE SHOWERS AND THUNDERSTORMS BY DAWN WED. LIGHT AND VARIABLE SFC FLOW WILL BECOME LIGHT SW TONIGHT...WHILE LIGHT NW FLOW ALOFT BECOMES LIGHT W THIS AFTERNOON AND THEN LIGHT SW TONIGHT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIOS: TIMING OF LIFTING AND DISSIPATION OF LOW STRATOCU...STRATUS AND FOG THIS MORNING MAY VARY. TIMING OF AND CONDITIONS IN THUNDERSTORMS LATE TODAY AND TONIGHT MAY VARY. IFR IS POSSIBLE RIGHT BENEATH ANY THUNDERSTORM LATE TODAY AND TONIGHT. THE THUNDERSTORMS MAY ALSO PRODUCE STRONG WIND GUSTS IN THE MIDDLE OHIO VALLEY THIS EVENING. TIMING AND EXTENT OF FOG AND STRATUS LATE OVERNIGHT TONIGHT MAY ALSO VARY FROM FCST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY L H M M M H H H H H H H HTS CONSISTENCY M H H H H H H H H H H H BKW CONSISTENCY H H H H H H M H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H M M M H H H H H H H H AFTER 18Z WEDNESDAY... IFR POSSIBLE IN ANY ROUND OF CONVECTION WED NT THROUGH FRI NT...AND IN LATE NT/EARLY MORNING POST RAIN FOG AND STRATUS THROUGH SAT MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...ARJ/TRM SHORT TERM...SL LONG TERM...JSH AVIATION...TRM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
633 PM EDT TUE AUG 19 2014 .SYNOPSIS... A MASSIVE RIDGE WILL BUILD OVER EAST-CENTRAL CANADA FOR THE NEXT WEEK. ANOTHER STRONG RIDGE WILL BUILD OVER THE SOUTHERN UNITED STATES. SHORT-WAVES EMBEDDED IN THE WEAK FLOW MOVING UNDER THE CANADIAN BLOCK WILL SLOW DOWN AND WEAKEN AS THEY MOVE THROUGH OUR REGION. THIS WILL LEAD TO A POTENTIALLY PROLONGED PERIOD OF UNSETTLED WEATHER. BUT IT SHOULD PROTECT US FROM THE LATE SEASON HEAT BUILDING TO OUR SOUTH. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... A PLEASANT EVENING IS IN STORE FOR MOST OF THE REGION AS A NEARLY N/S RIBBON OF RELATIVELY LOWER PWAT AIR /AROUND 1.0/ SLIDES EAST. CLOUDS...AND ISOLATED TO SCATTERED SHOWERS WILL AFFECT MAINLY THE LOWER SUSQ VALLEY THROUGH ABOUT 01Z WED. PRECIP CHCS WILL BE ESSENTIALLY ZERO ACROSS MUCH OF CENTRAL AND WESTERN PORTIONS OF THE CWA THROUGH 04-06Z...BEFORE A SHIELD OF ANVIL CIRRUS...THEN PRECIP ENTERS OUR NW ZONES IN ASSOCIATION WITH AN AREA TSRA MOVING ACROSS EXTREME SE MICH ATTM. TEMPS WILL SLOWLY COOL OFF FROM THE LOWER TO MID 70S THIS EVENING...BUT WILL LINGER AROUND 80F ACROSS THE FAR SE ZONES THROUGH 00Z. && .SHORT TERM /MIDNIGHT THROUGH 6 PM WEDNESDAY/... THE HIGH RES WRF ARW AND HRRR SHOWS CONVECTION MOVING ACROSS LAKE ERIE THIS EVENING AND INTO OUR FAR NW ZONES TWD 06Z /THOUGH THE HRRR HAS TRENDED TWD A FEW-SEVERAL HOUR LATER ONSET OF THE CONVECTION/. THIS AREA OF SHRA/TSRA SHOULD STEADILY WEAKEN/FRAGMENT AS IT ENCOUNTERS LOWER PWATS AND A COOLER/MORE STABLE LLVL ENVIRONMENT RESIDING OVER CENTRAL PENN. POPS AFTER 06Z WILL INCREASE GRADUALLY TO ABOUT 30-40 PERCENT BY DAYBREAK ACROSS THE WESTERN HALF OF THE CWA...BUT WILL REMIAN AOB 15 PERCENT FURTHER EAST ACROSS THE ENTIRE SUSQ VALLEY. PERVIOUS DISC BELOW... A SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... THE WEAKENING RIDGE OVER EASTERN CANADA WILL ALLOW FOR DIVERGENT FLOW AS THE UPPER LEVEL LOW SLOWLY MOVES EASTWARD. DAYTIME HEATING...DECREASING PRESSURE...MOIST SOUTHEASTERLY SFC FLOW...AND WEST TO NORTHWESTERLY FLOW ALOFT SHOULD ALLOW FOR ENOUGH SHEAR...FOR CHANCE TO LIKELY POPS EARLY WEDNESDAY EVENING. CAPE VALUES ARE LOW...WITH AN AVG OF 500-1K J/KG THROUGHOUT MOST OF CENTRAL PA. SO SCATTERED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE EARLY WEDNESDAY EVENING. THESE WILL SLOWLY FADE AS THE EVENING CONTINUES. THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY...WITH THE 850MB LOW MOVING THROUGH PA. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY THE AFTERNOON. HAVE CONTINUED POPS IN THE LIKELY CATEGORY BASED ON 12Z OPERATIONAL AND GEFS OUTPUT. DUE TO THE CHANGING POSITION AND TIMING OF THE LOW...HAVE SLIGHTLY LOWERED POPS ALONG THE SOUTHERN HALF OF THE CWA. THE SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MODEL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. BEFORE THE LOW PASSES...TEMPS COULD REACH UP TO THE LOW 80S. AFTER THURSDAY/S NUMEROUS SHOWERS AND THE ADVECTION OF COOLER TEMPS ALOFT...HIGH TEMPS SHOULD DROP BELOW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S THROUGH THE END OF THE WORK WEEK INTO THE WEEKEND. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARM UP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... BULK OF SHOWERS AND STORMS OVER WITH...JUST A FEW ACROSS THE FAR SOUTH. 21Z TAFS ADJUSTED FOR THIS. EARLIER DISCUSSION BELOW. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS. SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID TO LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... THU-SAT...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT CHC OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SUN...MAINLY VFR. STILL CHANCE OF SHRA IN THE MORNING. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT/GRUMM NEAR TERM...LAMBERT SHORT TERM...LAMBERT/GRUMM LONG TERM...FITZGERALD/CERU AVIATION...GRUMM/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
523 PM EDT TUE AUG 19 2014 .SYNOPSIS... A MASSIVE RIDGE WILL BUILD OVER EAST-CENTRAL CANADA FOR THE NEXT WEEK. ANOTHER STRONG RIDGE WILL BUILD OVER THE SOUTHERN UNITED STATES. SHORT-WAVES IN THE WEAK FLOW MOVING UNDER THE CANADIAN BLOCK WILL SLOW DOWN AND WEAKEN AS THEY MOVE THROUGH OUR REGION. THIS WILL LEAD TO A POTENTIALLY PROLONGED PERIOD OF UNSETTLED WEATHER. BUT IT SHOULD PROTECT US FROM THE LATE SEASON HEAT BUILDING TO OUR SOUTH. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... A WEAKLY ORGANIZED BROKEN LINE OF SHOWERS AND ISOLATED THUNDERSTORMS IS TRYING TO WORK ITS AWAY ACROSS OUR WEST-CENTRAL COUNTIES FROM CENTRE COUNTY DOWN TO THE MARYLAND BORDER. BUMPED UP POPS AND ADDED TEXTURE TO THE GRIDS WITH 3KM HRRR AND 4KM NAM ESTIMATED POPS/QPF. RADAR SHOWS VERY LIGHT RAIN. LOCAL GAGES SHOW ABOUT 0.10 IN WESTERN AREAS OF STATE COLLEGE. BUT SOME STREAKS ON RADAR OF 0.1 TO 0.4 INCHES. IN SOMERSET COUNTY...STRONGER CELLS SHOWS CLOSE TO AN INCH OF ESTIMATED RAINFALL. RADAR AND HRRR IMPLY BEST CHANCE RAIN WILL BE FROM CAMBRIA AND SOMERSET COUNTIES EASTWARD TO HUNTINGTON AND FRANKLIN COUNTY AS THE STRONGEST ELEMENTS HEAD SLOWLY EAST. THE 3KM AND 4KM MODELS IMPLY MOST OF THIS CONVECTION DIES OFF A FEW HOURS EITHER SIDE 6 PM. && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. MOST AREAS RAIN FREE IN HRRR AFTER 0000 UTC TONIGHT THROUGH 0600 UTC. BUT THE HRRR DOES SHOW OVERNIGHT CONVECTION IN THE MIDWEST MOVING INTO WESTERN PA AFTER 0600 UTC. CHANCE RAIN WILL CLEARER INCREASE BEFORE SUNRISE IN WESTERN AREAS. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... THE WEAKENING RIDGE OVER EASTERN CANADA WILL ALLOW FOR DIVERGENT FLOW AS THE UPPER LEVEL LOW SLOWLY MOVES EASTWARD. DAYTIME HEATING...DECREASING PRESSURE...MOIST SOUTHEASTERLY SFC FLOW...AND WEST TO NORTHWESTERLY FLOW ALOFT SHOULD ALLOW FOR ENOUGH SHEAR...FOR CHANCE TO LIKELY POPS EARLY WEDNESDAY EVENING. CAPE VALUES ARE LOW...WITH AN AVG OF 500-1K J/KG THROUGHOUT MOST OF CENTRAL PA. SO SCATTERED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE EARLY WEDNESDAY EVENING. THESE WILL SLOWLY FADE AS THE EVENING CONTINUES. THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY...WITH THE 850MB LOW MOVING THROUGH PA. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY THE AFTERNOON. HAVE CONTINUED POPS IN THE LIKELY CATEGORY BASED ON 12Z OPERATIONAL AND GEFS OUTPUT. DUE TO THE CHANGING POSITION AND TIMING OF THE LOW...HAVE SLIGHTLY LOWERED POPS ALONG THE SOUTHERN HALF OF THE CWA. THE SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MODEL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. BEFORE THE LOW PASSES...TEMPS COULD REACH UP TO THE LOW 80S. AFTER THURSDAY/S NUMEROUS SHOWERS AND THE ADVECTION OF COOLER TEMPS ALOFT...HIGH TEMPS SHOULD DROP BELOW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S THROUGH THE END OF THE WORK WEEK INTO THE WEEKEND. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARM UP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... BULK OF SHOWERS AND STORMS OVER WITH...JUST A FEW ACROSS THE FAR SOUTH. 21Z TAFS ADJUSTED FOR THIS. EARLIER DISCUSSION BELOW. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS. SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID TO LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... THU-SAT...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT CHC OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SUN...MAINLY VFR. STILL CHANCE OF SHRA IN THE MORNING. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS... NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD/CERU AVIATION...GRUMM/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
351 PM EDT TUE AUG 19 2014 .SYNOPSIS... A MASSIVE RIDGE WILL BUILD OVER EAST-CENTRAL CANADA FOR THE NEXT WEEK. ANOTHER STRONG RIDGE WILL BUILD OVER THE SOUTHERN UNITED STATES. SHORT-WAVES IN THE WEAK FLOW MOVING UNDER THE CANADIAN BLOCK WILL SLOW DOWN AND WEAKEN AS THEY MOVE THROUGH OUR REGION. THIS WILL LEAD TO A POTENTIALLY PROLONGED PERIOD OF UNSETTLED WEATHER. BUT IT SHOULD PROTECT US FROM THE LATE SEASON HEAT BUILDING TO OUR SOUTH. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... A WEAKLY ORGANIZED BROKEN LINE OF SHOWERS AND ISOLATED THUNDERSTORMS IS TRYING TO WORK ITS AWAY ACROSS OUR WEST-CENTRAL COUNTIES FROM CENTRE COUNTY DOWN TO THE MARYLAND BORDER. BUMPED UP POPS AND ADDED TEXTURE TO THE GRIDS WITH 3KM HRRR AND 4KM NAM ESTIMATED POPS/QPF. RADAR SHOWS VERY LIGHT RAIN. LOCAL GAGES SHOW ABOUT 0.10 IN WESTERN AREAS OF STATE COLLEGE. BUT SOME STREAKS ON RADAR OF 0.1 TO 0.4 INCHES. IN SOMERSET COUNTY...STRONGER CELLS SHOWS CLOSE TO AN INCH OF ESTIMATED RAINFALL. RADAR AND HRRR IMPLY BEST CHANCE RAIN WILL BE FROM CAMBRIA AND SOMERSET COUNTIES EASTWARD TO HUNTINGTON AND FRANKLIN COUNTY AS THE STRONGEST ELEMENTS HEAD SLOWLY EAST. THE 3KM AND 4KM MODELS IMPLY MOST OF THIS CONVECTION DIES OFF A FEW HOURS EITHER SIDE 6 PM. && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. MOST AREAS RAIN FREE IN HRRR AFTER 0000 UTC TONIGHT THROUGH 0600 UTC. BUT THE HRRR DOES SHOW OVERNIGHT CONVECTION IN THE MIDWEST MOVING INTO WESTERN PA AFTER 0600 UTC. CHANCE RAIN WILL CLEARER INCREASE BEFORE SUNRISE IN WESTERN AREAS. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... THE WEAKENING RIDGE OVER EASTERN CANADA WILL ALLOW FOR DIVERGENT FLOW AS THE UPPER LEVEL LOW SLOWLY MOVES EASTWARD. DAYTIME HEATING...DECREASING PRESSURE...MOIST SOUTHEASTERLY SFC FLOW...AND WEST TO NORTHWESTERLY FLOW ALOFT SHOULD ALLOW FOR ENOUGH SHEAR...FOR CHANCE TO LIKELY POPS EARLY WEDNESDAY EVENING. CAPE VALUES ARE LOW...WITH AN AVG OF 500-1K J/KG THROUGHOUT MOST OF CENTRAL PA. SO SCATTERED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE EARLY WEDNESDAY EVENING. THESE WILL SLOWLY FADE AS THE EVENING CONTINUES. THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY...WITH THE 850MB LOW MOVING THROUGH PA. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY THE AFTERNOON. HAVE CONTINUED POPS IN THE LIKELY CATEGORY BASED ON 12Z OPERATIONAL AND GEFS OUTPUT. DUE TO THE CHANGING POSITION AND TIMING OF THE LOW...HAVE SLIGHTLY LOWERED POPS ALONG THE SOUTHERN HALF OF THE CWA. THE SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MODEL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. BEFORE THE LOW PASSES...TEMPS COULD REACH UP TO THE LOW 80S. AFTER THURSDAY/S NUMEROUS SHOWERS AND THE ADVECTION OF COOLER TEMPS ALOFT...HIGH TEMPS SHOULD DROP BELOW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S THROUGH THE END OF THE WORK WEEK INTO THE WEEKEND. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARM UP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... RADAR SHOWS SOME ORGANIZED SHOWERS AND THUNDERSTORMS FROM NEAR KFIG SOUTH TO THE MARYLAND BORDER. THESE SHOWERS AND STORMS WILL SLOWLY MOVE EASTWARD THIS AFTERNOON. AREAS OF MVFR AND LOCALLY IFR ARE POSSIBLE ALONG THE LINE AND WITHIN THE SHOWERS AND THUNDERSTORMS. MODELS ALL SUGGEST POPCORN SHOWERS POSSIBLE OVER MOST OF CENTRAL PA AND THE MORE ORGANIZED ACTIVITY OVER THE SOUTHERN HALF OF THE STATE THROUGH THIS EVENING. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS.SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID- LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... TUE...MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED...MORNING FOG/LOW CLOUDS SHRA/TSRA LIKELY WEST CHANCE EAST. THU-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS... NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...CERU/FITZGERALD AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
206 PM EDT TUE AUG 19 2014 .SYNOPSIS... A MASSIVE RIDGE WILL BUILD OVER EAST-CENTRAL CANADA FOR THE NEXT WEEK. ANOTHER STRONG RIDGE WILL BUILD OVER THE SOUTHERN UNITED STATES. SHORT-WAVES IN THE WEAK FLOW MOVING UNDER THE CANADIAN BLOCK WILL SLOW DOWN AND WEAKEN AS THEY MOVE THROUGH OUR REGION. THIS WILL LEAD TO A POTENTIALLY PROLONGED PERIOD OF UNSETTLED WEATHER. BUT IT SHOULD PROTECT US FROM THE LATE SEASON HEAT BUILDING TO OUR SOUTH. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... A WEAKLY ORGANIZED BROKEN LINE OF SHOWERS AND ISOLATED THUNDERSTORMS IS TRYING TO WORK ITS AWAY ACROSS OUR WEST-CENTRAL COUNTIES FROM CENTRE COUNTY DOWN TO THE MARYLAND BORDER. BUMPED UP POPS AND ADDED TEXTURE TO THE GRIDS WITH 3KM HRRR AND 4KM NAM ESTIMATED POPS/QPF. RADAR SHOWS VERY LIGHT RAIN. LOCAL GAGES SHOW ABOUT 0.10 IN WESTERN AREAS OF STATE COLLEGE. BUT SOME STREAKS ON RADAR OF 0.1 TO 0.4 INCHES. IN SOMERSET COUNTY...STRONGER CELLS SHOWS CLOSE TO AN INCH OF ESTIMATED RAINFALL. RADAR AND HRRR IMPLY BEST CHANCE RAIN WILL BE FROM CAMBRIA AND SOMERSET COUNTIES EASTWARD TO HUNTINGTON AND FRANKLIN COUNTY AS THE STRONGEST ELEMENTS HEAD SLOWLY EAST. THE 3KM AND 4KM MODELS IMPLY MOST OF THIS CONVECTION DIES OFF A FEW HOURS EITHER SIDE 6 PM. && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. MOST AREAS RAINFREE IN HRRR AFTER 0000 UTC TONIGHT THROUGH 0600 UTC. BUT THE HRRR DOES SHOW OVERNIGHT CONVECTION IN THE MIDWEST MOVING INTO WESTERN PA AFTER 0600 UTC. CHANCE RAIN WILL CLEARER INCREASE BEFORE SUNRISE IN WESTERN AREAS. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... RADAR SHOWS SOME ORGANIZED SHOWERS AND THUNDERSTORMS FROM NEAR KFIG SOUTH TO THE MARYLAND BORDER. THESE SHOWERS AND STORMS WILL SLOWLY MOVE EASTWARD THIS AFTERNOON. AREAS OF MVFR AND LOCALLY IFR ARE POSSIBLE ALONG THE LINE AND WITHIN THE SHOWERS AND THUNDERSTORMS. MODELS ALL SUGGEST POPCORN SHOWERS POSSIBLE OVER MOST OF CENTRAL PA AND THE MORE ORGANIZED ACTIVITY OVER THE SOUTHERN HALF OF THE STATE THROUGH THIS EVENING. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS.SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID- LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... TUE...MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED...MORNING FOG/LOW CLOUDS SHRA/TSRA LIKELY WEST CHANCE EAST. THU-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS... NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
201 PM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... A WEAKLY ORGANIZED BROKEN LINE OF SHOWERS AND ISOLATED THUNDERSTORMS IS TRYING TO WORK ITS AWAY ACROSS OUR WEST-CENTRAL COUNTIES FROM CENTRE COUNTY DOWN TO THE MARYLAND BORDER. BUMPED UP POPS AND ADDED TEXTURE TO THE GRIDS WITH 3KM HRRR AND 4KM NAM ESTIMATED POPS/QPF. RADAR SHOWS VERY LIGHT RAIN. LOCAL GAGES SHOW ABOUT 0.10 IN WESTERN AREAS OF STATE COLLEGE. BUT SOME STREAKS ON RADAR OF 0.1 TO 0.4 INCHES. IN SOMERSET COUNTY...STRONGER CELLS SHOWS CLOSE TO AN INCH OF ESTIMATED RAINFALL. RADAR AND HRRR IMPLY BEST CHANCE RAIN WILL BE FROM CAMBRIA AND SOMERSET COUNTIES EASTWARD TO HUNTINGTON AND FRANKLIN COUNTY AS THE STRONGEST ELEMENTS HEAD SLOWLY EAST. THE 3KM AND 4KM MODELS IMPLY MOST OF THIS CONVECTION DIES OFF A FEW HOURS EITHER SIDE 6 PM. && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. MOST AREAS RAINFREE IN HRRR AFTER 0000 UTC TONIGHT THROUGH 0600 UTC. BUT THE HRRR DOES SHOW OVERNIGHT CONVECTION IN THE MIDWEST MOVING INTO WESTERN PA AFTER 0600 UTC. CHANCE RAIN WILL CLEARER INCREASE BEFORE SUNRISE IN WESTERN AREAS. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... RADAR SHOWS SOME ORGANIZED SHOWERS AND THUNDERSTORMS FROM NEAR KFIG SOUTH TO THE MARYLAND BORDER. THESE SHOWERS AND STORMS WILL SLOWLY MOVE EASTWARD THIS AFTERNOON. AREAS OF MVFR AND LOCALLY IFR ARE POSSIBLE ALONG THE LINE AND WITHIN THE SHOWERS AND THUNDERSTORMS. MODELS ALL SUGGEST POPCORN SHOWERS POSSIBLE OVER MOST OF CENTRAL PA AND THE MORE ORGANIZED ACTIVITY OVER THE SOUTHERN HALF OF THE STATE THROUGH THIS EVENING. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS.SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID- LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... TUE...MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED...MORNING FOG/LOW CLOUDS SHRA/TSRA LIKELY WEST CHANCE EAST. THU-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
128 PM EDT TUE AUG 19 2014 .SYNOPSIS... AN UPPER LOW OVR THE W GRT LKS WILL DRIFT SLOWLY SE ACROSS UPSTATE NY AND NEW ENG BY LATE THIS WEEK. A LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL RIDGE SOUTHWARD INTO PA DURING THE UPCOMING WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... LOW CLOUDS SLOWLY LIFTING AND MOVING TO THE EAST. RADAR HAS DETECTED SHOWERS WHICH DEVELOPED ON THE WESTERN EDGE OF THIS CLOUD SHIELD AND HAS MOVED INTO CLEARFIELD COUNTY. SOME HINTS OF WEAK CONVECTION IN THE HRRR AND 4KM NAM. USED THESE MODELS TO ADD TEXTURE TO THE FORECAST SHOWING SHOWERS AND ISOLATED THUNDERSTORMS DRIFTING ACROSS PENNSYLVANIA THIS MORNING AND AFTERNOON. TRIED TO KEEP POPS IN CHANCE RANGE AS THERE IS LIMITED ORGANIZATION TO THE CONVECTION. HOWEVER...3KM HRRR UPDATES FROM NCEPS EXPERIMENTAL HRRR SHOW DIFFERENT AREAS OF SHOWERS IN CENTRAL PA ALL AFTERNOON AND NOW IMPLY MORE ORGANIZED THUNDERSTORMS IN S-SE COUNTIES IN LATE AFTERNOON EVENING. SEE HOW THIS EVOLVES. SKIES SHOULD SLOWLY GET BETTER DURING DAY CENTRAL AREAS. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SREF AND NAM CONTINUE TO SHOW CHANCE TO SLIGHT CHANCE OF SHOWERS OVERNIGHT. THE SURGE OF CAPE AND PW INTO WESTERN PA IN THE SREF AND NAM...SIMILAR TO OLDER GEFS/GFS IMPLY SOME MORE ORGANIZED RAIN POSSIBLE ON WEDNESDAY. USED A BLEND TO GET THE POPS AND THE 12KM NAM TO ADD SOME TEXTURE TO CONVECTION AND RAIN AREA THAT APPEARS TO BE POISED TO MOVE WEST TO EAST ACROSS THE REGION WEDNESDAY. THE SREF POPS/PDF IMPLIES SHOWERS COMING INTO WEST AROUND 1500 UTC AND MOST OF CENTRAL TWO THIRDS OF REGION BY LATE EVENING. SREF IS KIND OF OPTIMISTIC SOUTHEAST PA COULD HAVE YET ANOTHER MOSTLY RAIN FREE DAY WEDNESDAY. THE KEY FEATURES ARE THE RETROGRADING RIDGE OVER EASTERN CANADA WHICH IS TAKING THE UMPH OUT OF THE SYSTEMS CUTTING UNDER THIS FEATURE. IN MOST MODELS THE NEAR 1SD ABOVE NORMAL PW SURGES WEAKEN AS THE MOVE INTO PA. THUS MORE OPTIMISTIC...SREF-LIKE IN THE WEST THAN THE EAST WITH RAINFALL AND NOT REALLY CONFIDENT GOING LIKELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THURSDAY LOOKS LIKE ANOTHER UNSETTLED DAY...AS UPPER LOW MAKES IT/S CLOSEST PASS TO PA...TRACKING ACROSS UPSTATE NY. COOL TEMPS ALOFT...COMBINED WITH DIURNAL HEATING...SHOULD YIELD NUMEROUS SHRA AND TSRA BY AFTN. HAVE RAISED POPS TO THE LIKELY CATEGORY BASED ON 00Z OPER AND GEFS OUTPUT. SOUTHERLY LL JET AND PLUME OF HIGH PWATS WILL HAVE PASSED NE OF THE AREA THURSDAY...LIMITING THE THREAT OF ANY HVY RAINFALL. MDL BLENDED QPF IS IN THE QUARTER TO HALF INCH RANGE THURSDAY. THE NUMEROUS SHOWERS AND COOLER TEMPS ALOFT WILL RESULT IN HIGH TEMPS BLW NORMAL FOR AUGUST...WITH MAXES MAINLY IN THE 70S. LATEST MED RANGE GUIDANCE POINTING TOWARD DRIER WX FRIDAY INTO EARLY NEXT WEEK...AS SUBTROPICAL HIGH IS PROGGED TO EDGE TOWARD THE REGION FROM THE MIDWEST. DAILY RING OF FIRE CONVECTION ON NE PERIPHERY OF THIS RIDGE WILL THREATEN WESTERN PA DURING THE FRI-SUN TIME FRAME...WHILE EASTERN PA IS LIKELY TO REMAIN DRY. DESPITE APPROACH OF UPPER RIDGE...NO BIG WARMUP EXPECTED...AS LARGE SFC HIGH OVR THE CANADIAN MARITIMES WILL CIRCULATE AN EASTERLY FLOW INTO CENTRAL PA. THERE MAY BE ISSUE WITH AM LOW CLOUDS/FOG DUE TO THE EXPECTED MOISTLY SERLY FLOW OVR THE AREA. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... RADAR SHOWS SOME ORGANIZED SHOWERS AND THUNDERSTORMS FROM NEAR KFIG SOUTH TO THE MARYLAND BORDER. THESE SHOWERS AND STORMS WILL SLOWLY MOVE EASTWARD THIS AFTERNOON. AREAS OF MVFR AND LOCALLY IFR ARE POSSIBLE ALONG THE LINE AND WITHIN THE SHOWERS AND THUNDERSTORMS. MODELS ALL SUGGEST POPCORN SHOWERS POSSIBLE OVER MOST OF CENTRAL PA AND THE MORE ORGANIZED ACTIVITY OVER THE SOUTHERN HALF OF THE STATE THROUGH THIS EVENING. THINGS SETTLE DOWN OVERNIGHT...MORE PATCHY FOG AND LOW CLOUDS.SO MORE AREAS OF MVFR AND IFR. WEDNESDAY WILL SEE RAIN AND SHOWERS LIKELY IN WESTERN PA BY MID- LATE MORNING SLOWLY SPREADING EAST. VFR IN EAST BUT AREAS MVFR LIKELY IN AM FOG AND THEN SHOWERS IN WESTERN AREAS. OUTLOOK... TUE...MAINLY VFR...WITH SHRA/TSRA POSSIBLE. WED...MORNING FOG/LOW CLOUDS SHRA/TSRA LIKELY WEST CHANCE EAST. THU-FRI...MORNING FOG CHANCES EACH DAY. OVERALL VFR...BUT INCREASING CHANCES OF MAINLY AFTERNOON SHRA/TSRA AND ASSOCIATED RESTRICTIONS. SAT...MAINLY VFR. STILL CHANCE OF SHRA...BUT DECREASING CHANCES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...FITZGERALD AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
319 PM CDT TUE AUG 19 2014 .DISCUSSION... UPPER FLOW IS NORTHWESTERLY THIS AFTERNOON WITH A SHORTWAVE AXIS IN PLACE FROM LAKE SUPERIOR SW THROUGH IO. AFTERNOON RADAR DEPICTS AN IMPULSE TO OUR NW WHICH WILL SWING OUR WAY OVERNIGHT. MID LEVEL RIDGING THIS AFTERNOON IS EXPECTED TO VACATE THE AREA BY EVENING. THIS WILL ACT TO PROMOTE A LITTLE EXTRA INSTABILITY OVERNIGHT. LATEST HRRR SHOWS THAT AN AREA OF CONVECTION WILL ENTER OUR NORTHWESTERN COUNTIES BETWEEN 01Z AND 03Z THIS EVENING. THE CONVECTION WILL THEN SPREAD SOUTHEAST BUT WILL FRAGMENT AND WEAKEN. WILL GO AHEAD AND INCLUDE 30-40 POPS FOR TONIGHT. A FEW OF THE STORMS COULD BECOME STRONG...PARTICULARLY ACROSS WESTERN AREAS THIS EVENING. OTW...WARM AND HUMID CONDITIONS TO CONTINUE OVERNIGHT. LOWS WILL GENERALLY BE IN THE LOWER 70S...UPPER 60S PLATEAU. NORTHWESTERLY FLOW WILL CONTINUE THROUGH WEDNESDAY. ASSOCIATED IMPULSES LOOK WEAK WITH THE LIMITED ENGAGEMENT OF APPRECIABLE MOISTURE. STILL THOUGH...CAP TO WEAKEN DURING THE AFTERNOON AND WILL THEREFORE INCLUDE SLIGHT POPS. FOR THURSDAY AND BEYOND THE PATTERN WILL CHANGE AND MORPH INTO A STRENGTHENING UPPER LEVEL RIDGING REGIME. BY THE WEEKEND...THE UPPER RIDGING WILL EXPAND OVER THE SOUTHEASTERN U.S. WITH THE UPPER HIGH CENTERED SOMEWHERE NEAR THE MS DELTA. THERMAL RIDGING TO STRENGTHEN AS WELL WITH SEPARATION OCCURRING ACROSS THE SOUTHEASTERN U.S. BY EARLY NEXT WEEK. THIS ALL EQUATES TO THE HOTTEST WEATHER WE HAVE SEEN ALL SUMMER. A MARKED INCREASE IN HUMIDITY LEVELS LOOKS SOMEWHAT QUESTIONABLE. MODELS HANG ON TO UPPER 60S AFTERNOON DEWPOINTS. THE LOWER LEVEL WIND FETCH LOOKS TO BE A BIT MORE LAND BASED AND THE HEIGHTENED LOWER LEVEL MOISTURE RETURNS LOOK RATHER SHALLOW IN DEPTH. THIS WILL ALLOW SOME AFTERNOON MIXING OF LOWER UPPER 60S DEWPOINTS DOWNWARD. THEREFORE...THE HEAT INDEX INFLUENCE WILL BE IN PLACE BUT WILL BE KEPT AT A RESPECTABLE AND NON-HIDEOUS LEVEL. AS FOR CONVECTION CHANCES DURING THE EXTENDED...MRH FIELDS LOOK TO BE IN THE 40-50% RANGE. 18Z CAP EROSION LOOKS LIKE IT WILL BE HARD PRESSED TO HAPPEN AS THE MID LEVELS WARM UNDERNEATH THE STRONG RIDGE. WILL THEREFORE BE LEAVING POPS OUT OF THE FCST...FOR THE MOST PART. FOR TEMPERATURES...HIGHS IN THE LOWER TO MID 90S FOR THE NEXT FEW DAYS. THEN...WE WILL SEE MID TO UPPER 90S FOR THE WEEKEND AND NEXT WEEK. OVERNIGHT LOWS WILL GENERALLY BE IN THE LOWER 70S FOR THE NEXT FEW DAYS...MID 70S FOR THE WEEKEND AND NEXT WEEK. OF COURSE...A LITTLE COOLER THROUGHOUT THE FCST FOR THE PLATEAU AREA. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 73 93 74 95 / 30 20 20 05 CLARKSVILLE 71 94 72 95 / 40 20 20 05 CROSSVILLE 67 88 68 90 / 30 30 20 20 COLUMBIA 72 94 73 95 / 30 20 10 0 LAWRENCEBURG 71 95 71 95 / 30 20 10 0 WAVERLY 71 94 72 95 / 40 20 10 05 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
252 PM CDT TUE AUG 19 2014 .SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT) ISSUED AT 252 PM CDT TUE AUG 19 2014 WATER VAPOR IMAGERY COUPLED WITH RAP 500MB ANALYSIS SHOWING A MID- LEVEL LOW OVER WESTERN UPPER MICHIGAN. COLD POOL ALOFT ASSOCIATED WITH THE LOW PRODUCING WIDESPREAD CUMULUS/STRATOCUMULUS FIELD ACROSS THE FORECAST AREA WITH RADAR EVEN SHOWING A FEW SHOWERS POPPING UP ACROSS NORTHERN MN INTO NORTHERN WI. OTHERWISE...TEMPERATURE ACROSS THE ARX FORECAST AREA WERE IN THE 70-80 DEGREE RANGE. FOR TONIGHT...COULD SEE A FEW SHOWERS NORTHEAST OF I-94 THIS EVENING BUT THEN EXPECTING CLOUDS TO DIMINISH LATE IN THE EVENING AND THROUGH THE OVERNIGHT HOURS AS A RIDGE OF HIGH PRESSURE MOVES OVERHEAD. THIS WILL SET UP FAVORABLE FOG POTENTIAL OVERNIGHT/EARLY WEDNESDAY MORNING...ESPECIALLY FAVORED RIVER VALLEY LOCATIONS. THINKING AREAS SOUTHWEST OF I-94 WILL BE MOST IMPACTED WHERE CONFIDENCE IS HIGHER FOR CLEARING SKY CONDITIONS EXISTS. HELD OFF ON DENSE FOG ADVISORY FOR NOW BASED ON INPUT FROM SURROUNDING OFFICES...BUT EVENING FORECASTER WILL HAVE TO MONITOR CLOSELY FOR POSSIBLE FOG HEADLINE. LOOK FOR LOWS TONIGHT IN THE MIDDLE 50S TO THE LOWER 60S. AFTER AREAS OF MORNING FOG...PLAN ON THE RIDGE OF HIGH PRESSURE TO KEEP THE FORECAST AREA DRY THROUGH WEDNESDAY. AN APPROACHING WARM FRONT FROM THE CENTRAL PLAINS/MID-MISSISSIPPI RIVER VALLEY WILL LIKELY SPARK A FEW SHOWERS AND THUNDERSTORMS...BUT PRETTY CONFIDENT THESE WILL REMAIN SOUTH OF THE AREA. OTHERWISE...EXPECTING HIGH TEMPERATURES TO TOP OFF IN THE MID 70S TO THE LOWER 80S. LOOK FOR SHOWERS AND THUNDERSTORMS TO BECOME LIKELY BY LATE WEDNESDAY NIGHT AS THE WARM FRONT CONTINUES TO APPROACH THE REGION. ALL MODELS SHOW 850MB MOISTURE TRANSPORT INCREASING INTO/OVER THE FRONT...WITH BEST AXIS OF MOISTURE PLUME REMAINING JUST WEST OF THE FORECAST AREA. IN FACT...THE GFS/NAM SHOWING PRECIPITABLE WATER VALUES SURGING INTO THE 1.5-2 INCH RANGE. THIS COULD LEAD TO SOME LOCALIZED HEAVIER RAINFALL AS WARM CLOUD LAYER DEPTH INCREASE TO AROUND 4KM BY MORNING. MAY NEED TO MONITOR THE POTENTIAL FOR A FEW SEVERE THUNDERSTORMS WITH LARGE HAIL INITIALLY WITH THE INCOMING CONVECTION AS NAM INDICATING 1-6KM MUCAPE IN THE 2500-3500J/KG RANGE COUPLED WITH 25-35KT BULK SHEAR. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 252 PM CDT TUE AUG 19 2014 MODELS SHOWING THE WARM FRONT PUSHING NORTHEAST THROUGH THE AREA ON THURSDAY FOR THE CONTINUED LIKELIHOOD OF SHOWERS AND THUNDERSTORMS. MODELS ALSO SHOWING 850MB MOISTURE TRANSPORT WANING THROUGH THE MORNING HOURS AND EVENTUAL CAPPING ALONG AND WEST OF THE MISSISSIPPI DURING THE AFTERNOON HOURS. AS SUCH...DIVIDED POPS INTO MORNING/AFTERNOON TIME PERIODS. STILL LOOKING AT THE POTENTIAL FOR SOME LOCALIZED HEAVY RAINFALL THROUGH THE MORNING HOURS WITH PRECIPITABLE WATER VALUES LINGERING IN THE 1.5 TO 2 INCH RANGE. OTHERWISE...LOOK FOR SUBSTANTIALLY MORE HUMID CONDITIONS AS DEW POINTS CREEP UP INTO THE LOWER 70S. THESE DEW POINTS COMBINED WITH DAYTIME HIGHS WELL INTO THE 80S FOR MOST OF THE AREA ARE EXPECTED TO PRODUCE HEAT INDICES IN THE 90 TO 100 DEGREE...HIGHEST ALONG AND WEST/SOUTH OF THE MISSISSIPPI/WISCONSIN RIVERS. FOR THURSDAY NIGHT THROUGH THE REST OF THE PERIOD...FORECAST CONFIDENCE WANES FAIRLY RAPIDLY. MODEL CONSENSUS SHOWS A MID-LEVEL RIDGE TRYING TO ESTABLISH ITSELF OVER THE CENTRAL CONUS. HOWEVER...MESSY FLOW WITH MONSOONAL TAP WILL BE IN PLACE ACROSS THE INTERMOUNTAIN/PLAINS REGION. TIMING OF THESE WAVES PRETTY UNCERTAIN AT THIS TIME. AS SUCH...WILL KEEP LOW-MEDIUM RANGE SHOWER/THUNDERSTORM CHANCES IN THROUGH THE PERIOD. TEMPERATURES THROUGH THE PERIOD LOOK TO STAY AT OR A FEW DEGREES ABOVE NORMAL THROUGH THE WEEKEND...WITH PERHAPS SOME COOLING EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1222 PM CDT TUE AUG 19 2014 LOW STRATUS THIS MORNING AT KLSE AND KRST HAS LIFTED TO ABOVE 3000 FT AGL AND EXPECT VFR CONDITIONS TO PERSIST THROUGH THIS AFTERNOON AND EVENING. OVERNIGHT SET-UP STILL VERY FAVORABLE FOR FOG WITH HIGH PRESSURE BUILDING ACROSS THE REGION RESULTING IN CLEARING SKIES AND CALM WIND. BASED ON LATEST MODEL GUIDANCE...BEGAN LIFR CONDITIONS AT KLSE AT 08Z WITH IMPROVEMENT EXPECTED AFTER 15Z. FOG EXTENT AT KRST A BIT LESS CERTAIN...SO WILL KEEP WITH THE IDEA OF VISIBILITY REDUCTIONS TO 1 SM AT 10Z WITH THE POTENTIAL FOR FURTHER RESTRICTIONS. && .HYDROLOGY...WEDNESDAY NIGHT INTO THURSDAY ISSUED AT 252 PM CDT TUE AUG 19 2014 THERE IS THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS WITH THE POTENTIAL FOR HEAVY RAINFALL WEDNESDAY NIGHT INTO THURSDAY MORNING. EXPECTING FAIRLY WIDESPREAD 1/4 TO 3/4 INCH RAINFALL WITH LOCALIZED GREATER THAN 1 INCH AMOUNTS. THIS RAINFALL COMBINED WITH RECENT POCKETS OF HEAVY RAINS ACROSS PORTIONS OF THE FORECAST AREA COULD LEAD TO SOME LOCALIZED FLOODING CONCERNS. WILL KEEP A CLOSE EYE ON LOCALIZED FLOODING CONCERN AND THE POTENTIAL FOR A FLASH FLOOD WATCH HEADLINE WEDNESDAY NIGHT INTO THURSDAY MORNING ONCE CONFIDENCE INCREASES ON EXACTLY WHERE THE HEAVIER RAINFALL WILL OCCUR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...ROGERS HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
250 PM MDT TUE AUG 19 2014 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 250 PM MDT TUE AUG 19 2014 THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS WHERE THE CONVECTION WILL BREAK OUT THIS AFTERNOON AND HOW MUCH CONVECTION WILL BREAK OUT AHEAD OF THE JET STREAK MOVING ACROSS THE ROCKIES TONIGHT. LATEST VISIBLE IMAGERY WAS SHOWING SOME ACCAS DEVELOPING ACROSS NORTHEAST COLORADO NEAR THE SURFACE TROF. THIS AREA MAY END UP BEING THE FIRST AREA TO FIRE UP THIS AFTERNOON. HOWEVER...IT MAY TRY TO IGNITE JUST EAST OF THE LARAMIE AND FRONT RANGES AS WELL WHERE WE HAVE HAD QUITE A BIT OF SUNSHINE. IN FACT...WE ARE STARTING TO SEE A LITTLE BIT OF ACCAS OVERHEAD AND CONVECTION DEVELOPING ALONG THE FRONT RANGE. MODELS ARE PROJECTING MIXED LAYER CAPES TO APPROACH 1500 J/KG THIS AFTERNOON WITH VERY LIMITED CAP. 0-6KM SHEAR VALUES (~30KTS) MAY ALSO BE FAVORABLE FOR A FEW STRONG TO SEVERE STORMS. AT THIS POINT...IT LOOKS THE HRRR IS STARTING TO BREAK OUT CONVECTION JUST EAST OF CHEYENNE AFTER 21Z WITH THE BULK OF THIS CONVECTION PUSHING GENERALLY EAST AT AROUND 20KTS. A FEW OF THESE STORMS MAY HAVE THE POTENTIAL TO PRODUCING STRONG WINDS AND HAIL IN THE PANHANDLE THIS AFTERNOON. LATEST SURFACE ANALYSIS WAS ALSO SHOWING SOME WINDS BACKING TO THE SOUTHEAST IN THE PANHANDLE. WE WILL ALSO NEED TO WATCH THAT AS THE AFTERNOON WEARS ON...ESPECIALLY IF THE STORMS GET GOING IN THAT REGION. ANOTHER CONCERN IS THE NAM IS SHOWING A 500MB JET STREAK MOVING OUT OF NORTHEAST COLORADO EARLY THIS EVENING WHICH MAY HELP ENHANCE THE SHEAR ACROSS THE PANHANDLE. IF CONVECTION IS ON GOING IN THAT REGION AS THIS JET STREAK MOVES ACROSS WE MAY HAVE MORE OF A SEVERE POTENTIAL. THEREFORE...IT WILL BE A MATTER OF TIMING ON HOW THINGS COME TOGETHER LATE THIS AFTERNOON AND EVENING. TONIGHT THE MODELS ARE SHOWING A FAIRLY STRONG UPPER LEVEL JET MOVING THROUGH NORTHERN COLORADO AND LIFTING NORTHEAST INTO NORTHEAST WYOMING BY DAYBREAK WHICH WILL HELP ENHANCE UPPER LEVEL DIFFLUENCE. THE MODELS ARE EVEN IN FAIRLY GOOD AGREEMENT IN SHOWING A MID LEVEL CIRCULATION WITH THIS JET STREAK. AS A RESULT... WE WOULD NOT SURPRISED TO SEE A COMPLEX OF SHOWERS AND THUNDERSTORMS DEVELOP ACROSS THE WESTERN HALF OF THE FORECAST AREA OVERNIGHT ALONG WITH THE POTENTIAL FOR HEAVY RAINFALL DUE TO PRECIPITABLE WATER VALUES AROUND 1 INCH. NOT EXPECTING MUCH IN THE WAY OF FLOODING SINCE THIS COMPLEX SHOULD BE FAIRLY PROGRESSIVE. WE DID BUMP UP POPS ACROSS THE NORTHERN HALF OF THE AREA TONIGHT TO REFLECT THIS POTENTIAL. WEDNESDAY-THURSDAY NIGHT: THE MID LEVEL CIRCULATION IS PROGGED TO CONTINUE LIFTING NORTHEAST WHICH WILL TAKE THE BULK OF THE CONVECTION NORTHEAST OF THE FORECAST AREA BY MID MORNING. THIS WILL LEAVE A FAIRLY BROAD AREA OF SUBSIDENCE IN THE MORNING IN THE WAKE OF THE CONVECTION...BUT WE MAY MORE CONVECTION DEVELOP IN THE AFTERNOON ACROSS THE MOUNTAINS AS UPSLOPE FLOW COMMENCES WITH LEFTOVER RESIDUAL MOISTURE. OTHERWISE...THE REMAINDER OF THE AREA EAST OF THE LARAMIE RANGE SHOULD REMAIN FAIRLY DRY WITH HIGHS GENERALLY IN THE 80S. THE NEXT CHANCE OF SHOWERS AND THUNDERSTORMS IS PROGGED TO TAKE PLACE ON THURSDAY AFTERNOON AS ANOTHER UPPER LEVEL WAVE LIFTS NORTHEAST OUT OF COLORADO AND PUSHES THROUGH AREAS EAST OF THE LARAMIE RANGE THURSDAY AFTERNOON INTO THURSDAY NIGHT. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 250 PM MDT TUE AUG 19 2014 AN UPPER LOW AND ASSOCIATED TROUGH OVER THE PACIFIC NW FRIDAY WILL MOVE SLOWLY EAST TOWARDS THE AREA FRIDAY THROUGH SATURDAY... SWINGING BY THE AREA ON SUNDAY. THIS WILL COMBINE WITH AT LEAST RESIDUAL MONSOONAL MOISTURE TO KEEP CHANCES FOR SHOWERS AND TSTMS GOING OVER MOST AREAS THROUGH SATURDAY NIGHT. WILL CONTINUE TO LEAN TOWARDS THE EC SOLUTION AS IT HAS BEEN FAIRLY CONSISTENT WITH THIS FEATURE. WARM TEMPS WILL CONTINUE THROUGH SATURDAY THEN A DECENT COOL FRONT WILL PASS ACROSS SAT NIGHT LEAVING A DRIER AND MILD DAY FOR THE CWA SUNDAY. CONTINUED MILD ON MONDAY WITH THE CWA ON THE SOUTHERN PORTION OF BROAD CYCLONIC UPPER FLOW THAT WILL BE OVER THE NORTHERN PART OF THE COUNTRY. A SECOND UPPER SHORTWAVE SHOULD PASS BY TUESDAY BRINGING A REINFORCING SHOT OF COOLER AIR AND A CHANCE FOR SOME PRECIPITATION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING) ISSUED AT 1123 AM MDT TUE AUG 19 2014 MID/HIGH CLOUDS WILL SPREAD ACROSS THE AREA THIS AFTERNOON AS A SURGE OF MONSOONAL MOISTURE MOVES IN FROM THE SW. WDLY SCTD SHWRS AND TSTMS DEVELOPING THIS AFTERNOON OVER AND NR THE SE WY MTNS WITH SOME SHOWERS CONTINUING TONIGHT MAINLY OVER WESTERN TERMINALS. BRIEF MVFR CIGS WITH ANY ACTIVITY. && .FIRE WEATHER... ISSUED AT 1056 AM MDT TUE AUG 19 2014 FIRE WEATHER CONCERNS TO REMAIN MINIMAL FOR THE REST OF THE WEEK WITH NON-CRITICAL WEATHER CONDITIONS EXPECTED. SOME WETTING RAINS SHOULD OCCUR OVER AT LEAST PARTS OF THE AREA OVER THE NEXT COUPLE DAYS AS A SURGE OF MONSOONAL MOISTURE PASSES OVER THE REGION AND INCREASES PRECIPITATION. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...REC LONG TERM...RE AVIATION...RE FIRE WEATHER...RE