Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/17/14


AREA FORECAST DISCUSSION
NWS TUCSON AZ
903 AM MST FRI AUG 15 2014 .SYNOPSIS...THUNDERSTORM CHANCES REMAIN IN THE FORECAST INTO EARLY NEXT WEEK. SOME STORMS WILL PRODUCE HEAVY RAIN THAT MAY LEAD TO FLOODING. && .DISCUSSION...THUNDERSTORMS ONGOING THIS MORNING TRIGGERED BY SHORT WAVE TROUGH DISTINCTLY SHOWING UP ON WATER VAPOR IMAGERY TRACKING EASTWARD. HAVE RAISED POPS FROM TUCSON EASTWARD THIS MORNING AS A RESULT. HRRR AND 12Z NAM PICKING UP ON THIS. THEY ARE ALSO INDICATING THAT MID LEVEL FLOW WILL BECOME NORTHEASTERLY BEHIND THIS SYSTEM AND SHOW STORMS MOVING OFF THE RIM TOWARD THE SW DURING THE LATE AFTERNOON HOURS TODAY. THUS HAVE RAISED POPS A BIT TO THE EAST THIS AFTERNOON AS WELL. HAVE LOWERED TEMPERATURES A FEW DEGREES...ESPECIALLY IN EASTERN AREAS WHERE CLOUDS AND STORMS WILL RESIDE FOR A LONGER TIME TODAY...KD && .AVIATION...VALID THRU 16/18Z. ISOLATED TO SCATTERED TSRA ARE EXPECTED THROUGH THIS EVENING...ESPECIALLY EAST OF A LINE FROM KOLS-KTUS-KSOW. SOME TSRA WILL PRODUCE LOCAL IFR CONDITIONS IN +RA ALONG WITH GUSTS TO 45 KTS. OTHERWISE...SURFACE WIND WILL GENERALLY BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...DAILY ROUNDS OF THUNDERSTORMS WILL CONTINUE INTO NEXT WEEK ACROSS AT LEAST PARTS OF SOUTHEAST ARIZONA. HEAVY RAINS...LIGHTNING AND OUTFLOW WINDS WILL BE THE MAIN THUNDERSTORM IMPACTS. && .PREV DISCUSSION...ENOUGH MOISTURE WILL RESIDE ACROSS SOUTHEAST ARIZONA THROUGH THE WEEKEND FOR SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. REALLY CAN`T PICK OUT WHICH DAY WILL BE THE MOST ACTIVE. HOWEVER MODELS ARE SUGGESTING THAT THE INTERNATIONAL BORDER AREAS WILL HAVE THE BEST CHANCES FOR THUNDERSTORMS...SOME WITH HEAVY RAIN. HIGHS WILL GENERALLY BE SEVERAL DEGREES ABOVE NORMAL. MOISTURE INCREASING NEXT WEEK UNDER SOUTHERLY FLOW ALOFT WITH LOW PRESSURE TO OUR WEST AND HIGH PRESSURE TO THE EAST. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
246 PM MDT FRI AUG 15 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 244 PM MDT FRI AUG 15 2014 CONVECTION THIS AFTERNOON HAS BEEN MORE SPARSE TODAY VS YESTERDAY...AT LEAST AS OF 20Z. HOWEVER...THE MTNS HAVE HAD MORE SUN TODAY...AND THUNDERSTORMS ARE FIRING OVER THE MOUNTAINS ALONG THE LEADING EDGE OF A WEAK SHORTWAVE MOVING INTO WESTERN CO. VARIOUS HIGH RES MODELS INCREASE THUNDERSTORM COVERAGE ACROSS THE MOUNTAINS...THEN SPREAD THEM EASTWARD INTO THE ADJACENT PLAINS DURING THE AFTERNOON AND EVENING HOURS. SFC DEW POINTS HAVE BEEN LOWER TODAY...DROPPING OFF INTO THE LOWER 40S AND EVEN SOME UPPER 30S ACROSS THE MOUNTAINS...WITH UPPER 40S TO MID 50S ACROSS THE PLAINS...AND THIS HAS LIMITED CAPE TO AROUND 500 J/KG ACCORDING TO SPC MESO ANALYSIS. PRECIP WATERS ARE RUNNING LOWER AS WELL...AROUND 80% OF NORMAL IN THE NORTH TO 130% OF NORMAL IN THE SOUTH BASED ON THE BLENDED TPW SATELLITE PRODUCT. THUS...THUNDERSTORMS SHOULD NOT BE AS EFFICIENT HEAVY RAINFALL PRODUCERS AS THEY WERE YESTERDAY. THAT SAID...THERE IS STILL SUFFICIENT MOISTURE FOR LOCALLY HEAVY RAIN WITH THE STRONGER STORMS. IF ONE OF THESE HITS BURN SCARS OR AREAS OF STEEP TERRAIN...THEN LOCALIZED FLASH FLOODING WILL STILL BE A CONCERN. FORTUNATELY...STORMS APPEAR TO BE MOVING PRETTY GOOD (SOUTHEAST AT 15 MPH)...WHICH MAY LIMIT THREAT SOME. HRRR SUGGESTS GREATEST THREAT WINDOW FOR THE WALD0 WILL BE FROM 21Z-00Z. THE PAPOOSE AND WEST FORK BURN SCARS AS WELL AS THE CONTINENTAL DIVIDE WILL SEE THE GREATEST THREAT BETWEEN 20Z AND 00Z. THUNDERSTORMS MAY MOVE OFF INTO THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND EVENING...BUT THEY DON`T LOOK TOO ORGANIZED AND THERE ISN`T MUCH OF A LOW LEVEL JET TO HELP SUSTAIN CONVECTION AFTER DARK...SO WILL END MOST POPS BY MIDNIGHT. SATURDAY LOOKS EVEN DRIER THAN TODAY AS PRECIPITABLE WATERS FALL OFF TO LESS THAN AN .75 INCHES ALONG/WEST OF I-25. STILL ENOUGH MOISTURE FOR ISOLATED DIURNAL THUNDERSTORMS...BUT COVERAGE SHOULD BE EVEN LOWER. STILL ENOUGH MOISTURE FOR LOCALLY HEAVY RAIN WITH THE STRONGER CELLS...BUT THREAT SHOULD BE LOWER DUE TO THE LIMITED COVERAGE. TEMPERATURES TOMORROW SHOULD BE A FEW DEGREES WARMER THAN TODAY. -KT .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 244 PM MDT FRI AUG 15 2014 EXTENDED FORECAST FOR SE CO LOOKS PRETTY TYPICAL FOR THE MIDDLE OF AUGUST. DAILY STORM CHANCES AND TEMPS AROUND 90 DEGREES FOR THE PLAINS. MAIN QUESTION WILL BE THE PROGRESSION OF A W COAST CUTOFF LOW AND PACNW TROUGH...ESPECIALLY LATE IN THE PERIOD. SAT NIGHT...CONVECTION SHOULD BE WRAPPING UP PRETTY EARLY AFTER SUNSET. WILL LEAVE HIGHEST POPS SAT EVE OVER THE RATON MESA AND FAR SERN PLAINS...WHERE THE MODELS ARE FOCUSING THE HEAVIEST QPF. SUNDAY...A SHORT WAVE DISTURBANCE WILL PUSH THROUGH IN THE NW FLOW LATE IN THE DAY. LOOKS LIKE THE MAIN IMPACT FROM THIS DISTURBANCE WILL COME AFTER 00Z...AND BE FOCUSED ON THE PIKES PEAK REGION AND PALMER DVD. EXPECT STORMS TO DEVELOP OVER THE MTS SOMEWHAT LATER THAN USUAL...MOSTLY AFTER 20Z...AND IT WILL BE ISOLD-SCT IN COVERAGE. THE SHORTWAVE SHOULD RESULT IN MORE WIDESPREAD COVERAGE OF STORMS BUT THERE IS STILL SOME UNCERTAINTY ON HOW FAR WEST THE BULK OF THE DEVELOPING CLUSTER OF STORMS WILL BE. HAVE THE HIGHEST POPS FROM THE PIKES PEAK AREA SEW TO KLAA...FROM 00-03Z. SUNDAY SHOULD BE THE WARMEST DAY OF THE PERIOD AS H7 TEMPS CLIMB TO NR 17 DEG C IN THE AFTERNOON. COULD SEE A FEW SPOTS CLIMB INTO THE UPPER 90S OVER THE LOWER ARKANSAS VALLEY. MONDAY...THE MAIN FOCUS FOR ANY CONVECTION WILL BE OVER THE ERN MTS AS LIGHT UPSLOPE FLOW PERSISTS ON THE BACKSIDE OF THE TROUGH MOVING THROUGH THE UPPER MISS VALLEY. WILL KEEP ISOLD-SCT POPS THERE WITH MORE ISOLD ACTIVITY POSSIBLE OVER THE BALANCE OF THE ERN PLAINS AND SAN LUIS VALLEY. IF TRENDS CONTINUE...MAY BE ABLE TO DROP MENTIONABLE POPS FROM ALL BUT THE MTS ON MONDAY. TUESDAY...WILL SEE THE START OF A SWITCH BACK TO INCREASING MONSOONAL MOISTURE. THE CUTOFF OFF THE CA COAST MAY BEGIN TO RETROGRADE DURING THIS PERIOD...WHILE A TROUGH IN THE PACNW BEGINS MOVING INTO ID AND MT. THE ECMWF CONTINUES OT BE A LITTLE MORE AGGRESSIVE IN BRINGING A RETURN OF MONSOONAL MOISTURE TO THE AREA...WHILE THE GFS HOLDS BACK A BIT. LOW POPS LOOK APPROPRIATE FOR THE REGION...ISOLD FOR THE LOWER ELEVS AND SCT IN THE MTS. BY WED-FRI...THE PACNW TROUGH SHOULD START TO ADVANCE INTO THE NRN ROCKIES...AS THE UPPER HIGH TO OUR SW SHIFTS INTO ERN TX. THIS SHOULD BRING A RETURN TO A STRONGER MONSOONAL PATTERN...WITH MORE MOISTURE BEING DRAWN NWD FROM THE SUBTROPICS INTO WRN CO. WILL LEAVE LOW ENSEMBLE POPS INTACT FOR NOW...BUT IF TRENDS CONTINUE MAY HAVE TO SLOWLY RAMP UP POPS FOR THE END OF THE WEEK. ROSE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 244 PM MDT FRI AUG 15 2014 VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS. THUNDERSTORMS WILL MOVE OFF THE MOUNTAINS INTO THE ADJACENT LOWER ELEVATIONS DURING THE LATE AFTERNOON AND EVENING HOURS. KCOS AND KALS WILL HAVE THE BEST CHANCE OF SEEING A THUNDERSTORM IN THE VICINITY OF THE TERMINALS. ERRATIC GUSTY WINDS UP TO 40 KTS AND BRIEF MVFR CIGS/VIS WITH TSRA WILL BE THE MAIN STORM THREATS. THREAT DIMINISHES BY 02Z AND KCOS AND KPUB TERMINALS MAY SEE A BRIEF NORTH WIND SHIFT FROM THUNDERSTORM OUTFLOWS DURING THE LATE AFTERNOON AND EVENING. SKIES CLEAR OUT OVERNIGHT WITH ANOTHER ROUND OF MORE ISOLATED THUNDERSTORMS POSSIBLE OVER THE MOUNTAINS ON SATURDAY. THESE MAY HAVE A HARDER TIME MOVING OFF INTO THE ADJACENT LOWER ELEVATIONS SO TERMINALS ARE MORE LIKELY TO BE SPARED ON SATURDAY. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KT LONG TERM...ROSE AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1120 AM MDT FRI AUG 15 2014 .UPDATE... ISSUED AT 745 AM MDT FRI AUG 15 2014 BLENDED LATEST OBSERVATIONS INTO FRONT END OF FORECAST GRIDS. ALSO TWEAKED SKY COVER TO FIT LATEST SATELLITE TRENDS. NO OTHER CHANGES AT THIS TIME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM MDT FRI AUG 15 2014 ...MONSOONAL AIR MASS REMAINS BUT LESS OF A TRIGGER THAN YESTERDAY... THE AIR MASS OVER THE REGION REMAINS PLENTY MOIST...BUT THERE IS NOT SO MUCH OF TRIGGER TO GET THINGS GOING TODAY AS YESTERDAY. YESTERDAY...A FAIRLY STRONG SHORTWAVE MOVED THROUGH NORTHERN COLORADO...TRIGGERING SOME RATHER INTENSE RAINFALL OVER THE PIKES PEAK REGION...WITH GENERALLY WEAKER ACTIVITY ELSEWHERE. TODAY...THE OVERALL AIR MASS IS SIMILAR BUT THERE DOESN`T SEEM TO BE AS MUCH OF A DISTURBANCE AVAILABLE TO GET THINGS GOING. WATER VAPOR PICTURES THIS MORNING DO SHOW A SWIRL IN THE IMAGERY OVER NORTHWEST ARIZONA AND THE RUC DOES IDENTIFY A WEAK DEPRESSION ASSOCIATED WITH THIS SWIRL. HOWEVER...SHORT TERM MODELS DON`T DO MUCH WITH THE DEPRESSION THROUGH THE DAY. THE NAM12 DOES HINT AT A VERY WEAK PIECE OF ENERGY ROUNDING THE TOP OF THE RIDGE THIS AFTERNOON AND THEN DROPPING SOUTHEAST THROUGH THE PLAINS THIS EVENING. THIS MIGHT BE A PIECE OF THE ENERGY NEAR THE 4 CORNERS REGION...OR IT MIGHT JUST BE MODEL FEEDBACK TO CONVECTION DEVELOPING OVER THE MOUNTAINS. IN ANY EVENT...IT DOESN`T LOOK NEARLY AS STRONG AS YESTERDAY`S SHORTWAVE. SO...EXPECTING TODAY`S CONVECTION TO BE MORE TERRAIN DRIVEN...DEVELOPING OVER THE MOUNTAINS BY EARLY AFTERNOON...BEFORE DRIFTING SOUTHEASTWARD ACROSS THE PLAINS LATER IN THE AFTERNOON INTO THE EVENING. WITH THE MONSOON PLUME REMAINING OVER THE REGION...AND SURFACE DEWPOINTS REMAINING HIGH...THE POTENTIAL FOR ANY GIVEN THUNDERSTORM TO PRODUCE LOCALIZED FLASH FLOODING WILL CONTINUE...NOT ONLY FOR THE BURN SCARS...BUT FOR ANYWHERE AN INTENSE...SLOW MOVING STORM HAPPENS TO TRACK. THIS WILL BE THE PRIMARY WEATHER CONCERN TODAY...ALONG WITH LIGHTNING AND THE POSSIBILITY OF LOCAL THUNDERSTORM WIND BURSTS TO 40 OR 50 MPH. LW .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 400 AM MDT FRI AUG 15 2014 MODELS STRUGGLING WITH THE EXTENDED PERIOD WITH RUN TO RUN INCONSISTENCIES...AND HAVE NOT MADE MANY CHANGES TO THE GOING FORECAST. HIGH PRESSURE WILL CONTINUE ACROSS THE DESERT SOUTHWEST THROUGH EARLY NEXT WEEK WITH SEVERAL WEAK DISTURBANCES PASSING ACROSS COLORADO. THIS WILL KEEP THE MONSOON LIKE PATTERN GOING ACROSS THE STATE WITH MOISTURE BEING THE LIMITING FACTOR. EXPECT DAILY AFTERNOON AND EVENING CONVECTION ACROSS THE MOUNTAINS WHERE DIURNAL HEATING AND INSTABILITY WILL FAVOR THUNDERSTORM DEVELOPMENT. WHILE MOISTURE MAY BE MORE LIMITED...THUNDERSTORMS WILL STILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...AND FLASH FLOODING WILL CONTINUE TO BE AN ISSUE ON AREA BURN SCARS ALONG WITH AREAS THAT HAVE SEEN RECENT HEAVY RAIN. LESS CERTAINTY EXISTS ON THE EASTERN PLAINS. THE GFS CONTINUES TO PRODUCE DAILY ROUNDS OF THUNDERSTORMS THAT MOVE OFF THE MOUNTAINS AND INTO THE PLAINS EACH NIGHT. THE NAM AND ECMWF ARE LESS EXCITED ABOUT SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE PLAINS. FOR NOW HAVE LOW POPS THROUGH THE EVENING HOURS FOR THE PLAINS GIVEN THE UNCERTAINTY. CURRENT MODEL PROJECTIONS HAVE DECENT WAVES MOVING ACROSS THE REGION SUNDAY AND TUESDAY...WHICH MAY BE THE DAYS THAT SEE THE GREATEST THUNDERSTORM POTENTIAL FOR THE PLAINS. LACK OF MODEL CONSISTENCY BY LATE TUESDAY THROUGH THURSDAY LEADS TO LOW FORECAST CONFIDENCE. THE 00Z GFS DROPPED A LOW PRESSURE CENTER DOWN THE CALIFORNIA COAST...WITH A STRONG TROUGH DIGGING ACROSS THE PACIFIC NORTHWEST. A QUICK GLANCE OF THE 06Z RUN DOES NOT HAVE THIS LOW AT ALL...WITH A MORE BROAD PACIFIC NORTHWEST TROUGH. GIVEN THESE INCONSISTENCIES...HAVE CONTINUED THE LOW POPS ACROSS THE REGION ON WEDNESDAY AND THURSDAY...BUT THESE WILL NEED TO BE ADJUSTED BASED ON FUTURE MODEL GUIDANCE. TEMPERATURES WILL REMAIN WARM THROUGH THE EXTENDED PERIOD WITH UPPER 80S TO MID 90S ACROSS THE LOWER ELEVATIONS. MOZLEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1041 AM MDT FRI AUG 15 2014 THUNDERSTORMS SHOULD BE LESS WIDESPREAD TODAY THAN YESTERDAY AND THE ATMOSPHERIC MOISTURE HAS DECREASED SOME...BUT SEVERAL HIGH RES MODELS DEVELOP THUNDERSTORMS OVER THE MOUNTAINS AROUND NOON AND SPREAD THEM OFF INTO THE ADJACENT PLAINS AROUND 3 PM. ENOUGH ATMOSPHERIC MOISTURE REMAINS IN PLACE FOR A FEW EMBEDDED STRONG THUNDERSTORMS CAPABLE OF LOCALLY HEAVY RAINFALL...BRIEF MVFR CONDITIONS...AND ERRATIC WIND GUSTS UP TO 40 KTS. KCOS HAS THE BEST CHANCE OF THE 3 TERMINALS TO BE AFFECTED...THOUGH ITS STILL UNCLEAR IF IT WILL TAKE A DIRECT HIT. WILL MAINTAIN VCTS IN THE KCOS TAF...THOUGH WILL INCLUDE A TEMPO 15G30KT GROUP TO ACCOUNT FOR HIGHER LIKELIHOOD OF SEEING ERRATIC WIND GUSTS FROM NEARBY THUNDERSTORMS. KALS COULD ALSO SEE A VCTS...THOUGH PROBABILITY LOOKS A LITTLE LOWER THAN AT KCOS. KPUB HAS THE LEAST PROBABILITY OF BEING AFFECTED BY -TSRA...SO WILL LEAVE VCTS OUT FOR NOW...BUT THIS WILL NEED TO BE MONITORED AS HIGH RES MODELS ARE TRENDING TOWARDS BRINGING A BROKEN LINE OF THUNDERSTORMS THROUGH THE AREA BETWEEN 23Z-00Z. BOTH KCOS AND KPUB WILL SEE A BRIEF NORTH TO NORTHWEST WIND SHIFT DURING THE LATE AFTERNOON/EVENING DUE TO OUTFLOW FROM THUNDERSTORMS. SKIES CLEAR OUT OVERNIGHT AND SATURDAY APPEARS TO HAVE A LATER START AND EVEN A LESSER COVERAGE OF THUNDERSTORMS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...LW SHORT TERM...LW LONG TERM...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
746 AM MDT FRI AUG 15 2014 .UPDATE... ISSUED AT 745 AM MDT FRI AUG 15 2014 BLENDED LATEST OBSERVATIONS INTO FRONT END OF FORECAST GRIDS. ALSO TWEAKED SKY COVER TO FIT LATEST SATELLITE TRENDS. NO OTHER CHANGES AT THIS TIME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM MDT FRI AUG 15 2014 ...MONSOONAL AIR MASS REMAINS BUT LESS OF A TRIGGER THAN YESTERDAY... THE AIR MASS OVER THE REGION REMAINS PLENTY MOIST...BUT THERE IS NOT SO MUCH OF TRIGGER TO GET THINGS GOING TODAY AS YESTERDAY. YESTERDAY...A FAIRLY STRONG SHORTWAVE MOVED THROUGH NORTHERN COLORADO...TRIGGERING SOME RATHER INTENSE RAINFALL OVER THE PIKES PEAK REGION...WITH GENERALLY WEAKER ACTIVITY ELSEWHERE. TODAY...THE OVERALL AIR MASS IS SIMILAR BUT THERE DOESN`T SEEM TO BE AS MUCH OF A DISTURBANCE AVAILABLE TO GET THINGS GOING. WATER VAPOR PICTURES THIS MORNING DO SHOW A SWIRL IN THE IMAGERY OVER NORTHWEST ARIZONA AND THE RUC DOES IDENTIFY A WEAK DEPRESSION ASSOCIATED WITH THIS SWIRL. HOWEVER...SHORT TERM MODELS DON`T DO MUCH WITH THE DEPRESSION THROUGH THE DAY. THE NAM12 DOES HINT AT A VERY WEAK PIECE OF ENERGY ROUNDING THE TOP OF THE RIDGE THIS AFTERNOON AND THEN DROPPING SOUTHEAST THROUGH THE PLAINS THIS EVENING. THIS MIGHT BE A PIECE OF THE ENERGY NEAR THE 4 CORNERS REGION...OR IT MIGHT JUST BE MODEL FEEDBACK TO CONVECTION DEVELOPING OVER THE MOUNTAINS. IN ANY EVENT...IT DOESN`T LOOK NEARLY AS STRONG AS YESTERDAY`S SHORTWAVE. SO...EXPECTING TODAY`S CONVECTION TO BE MORE TERRAIN DRIVEN...DEVELOPING OVER THE MOUNTAINS BY EARLY AFTERNOON...BEFORE DRIFTING SOUTHEASTWARD ACROSS THE PLAINS LATER IN THE AFTERNOON INTO THE EVENING. WITH THE MONSOON PLUME REMAINING OVER THE REGION...AND SURFACE DEWPOINTS REMAINING HIGH...THE POTENTIAL FOR ANY GIVEN THUNDERSTORM TO PRODUCE LOCALIZED FLASH FLOODING WILL CONTINUE...NOT ONLY FOR THE BURN SCARS...BUT FOR ANYWHERE AN INTENSE...SLOW MOVING STORM HAPPENS TO TRACK. THIS WILL BE THE PRIMARY WEATHER CONCERN TODAY...ALONG WITH LIGHTNING AND THE POSSIBILITY OF LOCAL THUNDERSTORM WIND BURSTS TO 40 OR 50 MPH. LW .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 400 AM MDT FRI AUG 15 2014 MODELS STRUGGLING WITH THE EXTENDED PERIOD WITH RUN TO RUN INCONSISTENCIES...AND HAVE NOT MADE MANY CHANGES TO THE GOING FORECAST. HIGH PRESSURE WILL CONTINUE ACROSS THE DESERT SOUTHWEST THROUGH EARLY NEXT WEEK WITH SEVERAL WEAK DISTURBANCES PASSING ACROSS COLORADO. THIS WILL KEEP THE MONSOON LIKE PATTERN GOING ACROSS THE STATE WITH MOISTURE BEING THE LIMITING FACTOR. EXPECT DAILY AFTERNOON AND EVENING CONVECTION ACROSS THE MOUNTAINS WHERE DIURNAL HEATING AND INSTABILITY WILL FAVOR THUNDERSTORM DEVELOPMENT. WHILE MOISTURE MAY BE MORE LIMITED...THUNDERSTORMS WILL STILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...AND FLASH FLOODING WILL CONTINUE TO BE AN ISSUE ON AREA BURN SCARS ALONG WITH AREAS THAT HAVE SEEN RECENT HEAVY RAIN. LESS CERTAINTY EXISTS ON THE EASTERN PLAINS. THE GFS CONTINUES TO PRODUCE DAILY ROUNDS OF THUNDERSTORMS THAT MOVE OFF THE MOUNTAINS AND INTO THE PLAINS EACH NIGHT. THE NAM AND ECMWF ARE LESS EXCITED ABOUT SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE PLAINS. FOR NOW HAVE LOW POPS THROUGH THE EVENING HOURS FOR THE PLAINS GIVEN THE UNCERTAINTY. CURRENT MODEL PROJECTIONS HAVE DECENT WAVES MOVING ACROSS THE REGION SUNDAY AND TUESDAY...WHICH MAY BE THE DAYS THAT SEE THE GREATEST THUNDERSTORM POTENTIAL FOR THE PLAINS. LACK OF MODEL CONSISTENCY BY LATE TUESDAY THROUGH THURSDAY LEADS TO LOW FORECAST CONFIDENCE. THE 00Z GFS DROPPED A LOW PRESSURE CENTER DOWN THE CALIFORNIA COAST...WITH A STRONG TROUGH DIGGING ACROSS THE PACIFIC NORTHWEST. A QUICK GLANCE OF THE 06Z RUN DOES NOT HAVE THIS LOW AT ALL...WITH A MORE BROAD PACIFIC NORTHWEST TROUGH. GIVEN THESE INCONSISTENCIES...HAVE CONTINUED THE LOW POPS ACROSS THE REGION ON WEDNESDAY AND THURSDAY...BUT THESE WILL NEED TO BE ADJUSTED BASED ON FUTURE MODEL GUIDANCE. TEMPERATURES WILL REMAIN WARM THROUGH THE EXTENDED PERIOD WITH UPPER 80S TO MID 90S ACROSS THE LOWER ELEVATIONS. MOZLEY && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 400 AM MDT FRI AUG 15 2014 MONSOON MOISTURE PLUME REMAINS OVER FLIGHT AREA TODAY. UNLIKE YESTERDAY...THERE IS NOT MUCH OF A DISTURBANCE MOVING THROUGH TO HELP TRIGGER CONVECTION TODAY. HOWEVER...THE MOUNTAINS WILL BE A SUFFICIENT TRIGGER FOR AREAS IN A NEAR THE HIGHER TERRAIN...WITH SOME ACTIVITY DRIFTING SOUTHEAST ACROSS THE PLAINS DURING THE LATE AFTERNOON AND EVENING HOURS. PRIMARY STORM HAZARDS TODAY WILL INCLUDE LOCALIZED FLASH FLOODING... LIGHTNING AND WIND GUSTS UP TO 50 MPH. WITH COVERAGE TIED MOSTLY TO THE MOUNTAINS...KCOS IS THE MOST LIKELY TARGET FOR A THUNDERSTORM TODAY...WHILE KALS AND KPUB MAY BE FAR ENOUGH REMOVED FROM THE TERRAIN TO AVOID CONVECTION. SO...FOR NOW...WILL CONTINUE WITH CURRENT TERMINAL FORECAST OF POSSIBLE VCTS AT KCOS AFTER 21 OR 22Z...AND KEEP THUNDERSTORMS OUT OF THE FORECAST AT KALS AND KPUB. LOCAL MVFR/IFR/LIFR CONDITIONS POSSIBLE WITH ANY THUNDERSTORMS ACROSS THE AREA...PRIMARILY 18Z-06Z. LW && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...LW SHORT TERM...LW LONG TERM...MOZLEY AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
431 AM MDT FRI AUG 15 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM MDT FRI AUG 15 2014 ...MONSOONAL AIR MASS REMAINS BUT LESS OF A TRIGGER THAN YESTERDAY... THE AIR MASS OVER THE REGION REMAINS PLENTY MOIST...BUT THERE IS NOT SO MUCH OF TRIGGER TO GET THINGS GOING TODAY AS YESTERDAY. YESTERDAY...A FAIRLY STRONG SHORTWAVE MOVED THROUGH NORTHERN COLORADO...TRIGGERING SOME RATHER INTENSE RAINFALL OVER THE PIKES PEAK REGION...WITH GENERALLY WEAKER ACTIVITY ELSEWHERE. TODAY...THE OVERALL AIR MASS IS SIMILAR BUT THERE DOESN`T SEEM TO BE AS MUCH OF A DISTURBANCE AVAILABLE TO GET THINGS GOING. WATER VAPOR PICTURES THIS MORNING DO SHOW A SWIRL IN THE IMAGERY OVER NORTHWEST ARIZONA AND THE RUC DOES IDENTIFY A WEAK DEPRESSION ASSOCIATED WITH THIS SWIRL. HOWEVER...SHORT TERM MODELS DON`T DO MUCH WITH THE DEPRESSION THROUGH THE DAY. THE NAM12 DOES HINT AT A VERY WEAK PIECE OF ENERGY ROUNDING THE TOP OF THE RIDGE THIS AFTERNOON AND THEN DROPPING SOUTHEAST THROUGH THE PLAINS THIS EVENING. THIS MIGHT BE A PIECE OF THE ENERGY NEAR THE 4 CORNERS REGION...OR IT MIGHT JUST BE MODEL FEEDBACK TO CONVECTION DEVELOPING OVER THE MOUNTAINS. IN ANY EVENT...IT DOESN`T LOOK NEARLY AS STRONG AS YESTERDAY`S SHORTWAVE. SO...EXPECTING TODAY`S CONVECTION TO BE MORE TERRAIN DRIVEN...DEVELOPING OVER THE MOUNTAINS BY EARLY AFTERNOON...BEFORE DRIFTING SOUTHEASTWARD ACROSS THE PLAINS LATER IN THE AFTERNOON INTO THE EVENING. WITH THE MONSOON PLUME REMAINING OVER THE REGION...AND SURFACE DEWPOINTS REMAINING HIGH...THE POTENTIAL FOR ANY GIVEN THUNDERSTORM TO PRODUCE LOCALIZED FLASH FLOODING WILL CONTINUE...NOT ONLY FOR THE BURN SCARS...BUT FOR ANYWHERE AN INTENSE...SLOW MOVING STORM HAPPENS TO TRACK. THIS WILL BE THE PRIMARY WEATHER CONCERN TODAY...ALONG WITH LIGHTNING AND THE POSSIBILITY OF LOCAL THUNDERSTORM WIND BURSTS TO 40 OR 50 MPH. LW .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 400 AM MDT FRI AUG 15 2014 MODELS STRUGGLING WITH THE EXTENDED PERIOD WITH RUN TO RUN INCONSISTENCIES...AND HAVE NOT MADE MANY CHANGES TO THE GOING FORECAST. HIGH PRESSURE WILL CONTINUE ACROSS THE DESERT SOUTHWEST THROUGH EARLY NEXT WEEK WITH SEVERAL WEAK DISTURBANCES PASSING ACROSS COLORADO. THIS WILL KEEP THE MONSOON LIKE PATTERN GOING ACROSS THE STATE WITH MOISTURE BEING THE LIMITING FACTOR. EXPECT DAILY AFTERNOON AND EVENING CONVECTION ACROSS THE MOUNTAINS WHERE DIURNAL HEATING AND INSTABILITY WILL FAVOR THUNDERSTORM DEVELOPMENT. WHILE MOISTURE MAY BE MORE LIMITED...THUNDERSTORMS WILL STILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...AND FLASH FLOODING WILL CONTINUE TO BE AN ISSUE ON AREA BURN SCARS ALONG WITH AREAS THAT HAVE SEEN RECENT HEAVY RAIN. LESS CERTAINTY EXISTS ON THE EASTERN PLAINS. THE GFS CONTINUES TO PRODUCE DAILY ROUNDS OF THUNDERSTORMS THAT MOVE OFF THE MOUNTAINS AND INTO THE PLAINS EACH NIGHT. THE NAM AND ECMWF ARE LESS EXCITED ABOUT SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE PLAINS. FOR NOW HAVE LOW POPS THROUGH THE EVENING HOURS FOR THE PLAINS GIVEN THE UNCERTAINTY. CURRENT MODEL PROJECTIONS HAVE DECENT WAVES MOVING ACROSS THE REGION SUNDAY AND TUESDAY...WHICH MAY BE THE DAYS THAT SEE THE GREATEST THUNDERSTORM POTENTIAL FOR THE PLAINS. LACK OF MODEL CONSISTENCY BY LATE TUESDAY THROUGH THURSDAY LEADS TO LOW FORECAST CONFIDENCE. THE 00Z GFS DROPPED A LOW PRESSURE CENTER DOWN THE CALIFORNIA COAST...WITH A STRONG TROUGH DIGGING ACROSS THE PACIFIC NORTHWEST. A QUICK GLANCE OF THE 06Z RUN DOES NOT HAVE THIS LOW AT ALL...WITH A MORE BROAD PACIFIC NORTHWEST TROUGH. GIVEN THESE INCONSISTENCIES...HAVE CONTINUED THE LOW POPS ACROSS THE REGION ON WEDNESDAY AND THURSDAY...BUT THESE WILL NEED TO BE ADJUSTED BASED ON FUTURE MODEL GUIDANCE. TEMPERATURES WILL REMAIN WARM THROUGH THE EXTENDED PERIOD WITH UPPER 80S TO MID 90S ACROSS THE LOWER ELEVATIONS. MOZLEY && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 400 AM MDT FRI AUG 15 2014 MONSOON MOISTURE PLUME REMAINS OVER FLIGHT AREA TODAY. UNLIKE YESTERDAY...THERE IS NOT MUCH OF A DISTURBANCE MOVING THROUGH TO HELP TRIGGER CONVECTION TODAY. HOWEVER...THE MOUNTAINS WILL BE A SUFFICIENT TRIGGER FOR AREAS IN A NEAR THE HIGHER TERRAIN...WITH SOME ACTIVITY DRIFTING SOUTHEAST ACROSS THE PLAINS DURING THE LATE AFTERNOON AND EVENING HOURS. PRIMARY STORM HAZARDS TODAY WILL INCLUDE LOCALIZED FLASH FLOODING... LIGHTNING AND WIND GUSTS UP TO 50 MPH. WITH COVERAGE TIED MOSTLY TO THE MOUNTAINS...KCOS IS THE MOST LIKELY TARGET FOR A THUNDERSTORM TODAY...WHILE KALS AND KPUB MAY BE FAR ENOUGH REMOVED FROM THE TERRAIN TO AVOID CONVECTION. SO...FOR NOW...WILL CONTINUE WITH CURRENT TERMINAL FORECAST OF POSSIBLE VCTS AT KCOS AFTER 21 OR 22Z...AND KEEP THUNDERSTORMS OUT OF THE FORECAST AT KALS AND KPUB. LOCAL MVFR/IFR/LIFR CONDITIONS POSSIBLE WITH ANY THUNDERSTORMS ACROSS THE AREA...PRIMARILY 18Z-06Z. LW && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...LW LONG TERM...MOZLEY AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1135 PM MDT THU AUG 14 2014 .UPDATE... ISSUED AT 911 PM MDT THU AUG 14 2014 UPDATED FORECAST TO LOWER/REMOVE POPS OVER ALL BUT THE FAR SOUTHEAST PLAINS. UPDATE ISSUED AT 557 PM MDT THU AUG 14 2014 WITH HEAVY RAIN THREAT SHIFTING INTO NORTHEAST COLORADO THIS EVENING...AND ONLY VERY ISOLATED STORMS ALONG THE CONTINENTAL DIVIDE...WILL CANCEL FLASH FLOOD WATCH FOR ALL AREAS A LITTLE EARLIER THAN SCHEDULED. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 310 PM MDT THU AUG 14 2014 SHORTWAVE CURRENTLY MOVING ACROSS NORTHERN CO HAS INITIATED THUNDERSTORMS OVER THE PIKES PEAK REGION THIS AFTERNOON. HIGH PRECIPITABLE WATERS RUNNING 150+% OF NORMAL IS ALLOWING FOR EFFICIENT RAINFALL RATES AS EVIDENCED FROM RADAR KDP/S AND SPOTTER REPORTS. THERE HAVE ALSO BEEN SOME PEA SIZE HAIL REPORTS WITH THE STRONGER STORMS. AS THE SHORTWAVE CONTINUES TO DRAG ACROSS EASTERN COLORADO...THUNDERSTORMS WILL CONTINUE TO SPREAD EASTWARD ACROSS THE PLAINS. STORMS HAVE BEEN MOVING NORTHEAST AT 15 MPH...ENOUGH TO ABATE SOME OF THE FLASH FLOOD RISK...BUT NOT ENTIRELY NEGATE IT AS HEAVY RAINFALL RATES OF AROUND 2 INCHES PER HOUR CAN STILL CAUSE PROBLEMS FOR THE BURN SCARS AND URBAN AREAS. THUS WILL KEEP THE FLASH FLOOD WATCH GOING THROUGH 9 PM. BEEN A LITTLE HARDER TO GET STRONGER CONVECTION GOING OUT WEST ALONG THE CONTINENTAL DIVIDE AND SUSPECT THAT THREAT THERE IS RAPIDLY DIMINISHING AS STABILITY HAS BEEN A FACTOR WITH THE CLOUD COVER AND EARLIER RAINFALL. WILL KEEP THE WATCH GOING THROUGH THE PRIME HEATING HOURS...BUT SUSPECT THAT WE MAY BE ABLE TO TAKE DOWN THE WATCH BY 6 PM FOR CHAFFEE/LAKE COUNTIES AND THE EASTERN SAN JUANS AND LA GARITAS. THUNDERSTORMS WILL SPREAD EASTWARD ACROSS THE PLAINS THROUGH THE EVENING HOURS. LATEST HRRR SUGGESTS THAT THREAT FOR PIKES PEAK AREA MAY BE ENDED BY 6-7 PM. HIGHEST POPS THROUGH THE EVENING HOURS WILL BE ACROSS THE SOUTHEAST PLAINS AS THUNDERSTORMS DEVELOP ALONG SOUTHWARD ADVANCING COLD FRONT. APPEARS BEST LIFT MAY BE ACROSS NORTHWEST KANSAS AND EAST CENTRAL CO (KIOWA COUNTY) AS LOW LEVEL JET IMPINGES ON THE FRONT...SO WILL KEEP HIGHEST POPS UP THAT WAY. MOST OF THE ACTIVITY WILL BE DONE BY MIDNIGHT AS LINE OF THUNDERSTORMS MOVES EAST INTO KANSAS. A LITTLE LESS ACTIVE WEATHER IS EXPECTED TOMORROW. PRECIPITABLE WATERS WILL DROP OFF BELOW 1 INCH FOR THE I-25 CORRIDOR AND WESTWARD. STILL LOOKING AT SUFFICIENT MOISTURE FOR ISOLATED TO SCATTERED THUNDERSTORMS...SO STILL CAN`T RULE OUT HEAVY RAIN ON BURN SCARS AND POTENTIAL FOR FLASH FLOODING. BUT THREAT CERTAINLY LOOKS LOWER DUE TO THE MORE ISOLATED NATURE OF THESE STRONGER CELLS. GRIDS WILL CARRY MORE OF A DIURNAL POP TREND...WITH THUNDERSTORMS FIRING OVER THE MOUNTAINS AROUND NOON...THEN DEVELOPING/SPREADING EASTWARD ACROSS THE ADJACENT PLAINS DURING THE LATE AFTERNOON. -KT .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 310 PM MDT THU AUG 14 2014 FRIDAY NIGHT-THURSDAY...NOT MUCH CHANGE IN THE ONGOING FORECAST THROUGH THE EXTENDED PERIOD WITH FLAT UPPER LEVEL RIDGING REMAINING IN PLACE ACROSS THE GREAT BASIN THROUGH THE ROCKIES. THIS WILL KEEP MONSOONAL MOISTURE PLUME SOUTH AND SOUTHWEST OF THE STATE WITH WEAK WEST TO NORTHWEST FLOW ALOFT ACROSS THE STATE AND WEATHER SYSTEMS MOVING ACROSS THE NORTHERN TIER OF STATES AND INTO THE UPPER MIDWEST. THERE LOOKS TO BE ENOUGH RESIDUAL MOISTURE IN PLACE TO WORK WITH LATE SUMMER SOLAR HEATING TO KEEP ISOLATED TO SCATTERED AFTERNOON AND EVENING STORMS IN THE FORECAST OVER AND NEAR THE HIGHER TERRAIN...WITH A FEW STORMS POSSIBLY ROLLING ACROSS THE FAR SE PLAINS THROUGH THE LATE EVENING AND OVERNIGHT HOURS. STORMS THAT DO DEVELOP SHOULD BE GENERALLY HIGH BASED...THOUGH STILL CAN NOT RULE OUT LOCALIZED HEAVY RAINFALL AND SMALL HAIL WITH STRONGER CELLS. HARD TO PIN POINT BEST COVERAGE OF STORMS THOUGH COULD SEE INCREASED COVERAGE SUNDAY THROUGH SUNDAY NIGHT AND AGAIN TUESDAY AND TUESDAY NIGHT AS EMBEDDED DISTURBANCES MOVE ACROSS THE NORTHERN ROCKIES AND INTO THE HIGH PLAINS. WITH RIDGING IN PLACE...TEMPERATURES ACROSS THE AREA LOOK TO BE GENERALLY AT OR SLIGHTLY ABOVE LATE SUMMER AVERAGES THROUGH THE PERIOD. THERE COULD BE A CHANGE IN THE PATTERN INTO EARLY NEXT WEEKEND...AS A BROAD UPPER TROUGH TRIES TO CARVE OUT ACROSS THE WEST COAST OPENING THE DOOR TO INCREASING MOISTURE WITHIN DEVELOPING SOUTH TO SOUTHWEST FLOW ALOFT ACROSS THE DESERT SOUTHWEST AND INTO THE ROCKIES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1130 PM MDT THU AUG 14 2014 BACK EDGE OF TSRA JUST ABOUT INTO KANSAS AS OF 0530Z...AND EXPECT VFR CONDITIONS MOST AREAS OVERNIGHT INTO MIDDAY FRIDAY. ISOLATED TSRA WILL DEVELOP OVER THE MOUNTAINS 18Z-20Z FRI...AND A FEW STORMS MAY SPREAD TOWARD LOWER ELEVATIONS 22Z-02Z. HAVE INCLUDED A VCTS MENTION AT KCOS AFTER 22Z...BUT KEPT KPUB AND KALS CONVECTION FREE AT THIS POINT AS ODDS FOR STORMS AT BOTH SITES LOOK FAIRLY LOW. STORMS WILL DIMINISH QUICKLY IN THE EVENING WITH VFR CONDITIONS OVERNIGHT ALL AREAS. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PETERSEN SHORT TERM...KT LONG TERM...MW AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
935 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT AND EAST OF WESTERN NEW ENGLAND BY THE EARLY AFTERNOON ON SUNDAY. THIS FRONT WILL BE ACCOMPANIED WITH THE ISOLATED TO SCATTERED SHOWERS TONIGHT INTO SUNDAY MORNING. CONDITIONS IMPROVE LATER SUNDAY AND INTO EARLY NEXT WEEK AS HIGH PRESSURE RETURNS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 935 PM EDT...SHOWERS HAVE MOVED IN A TAD FASTER THAN PREVIOUSLY THOUGHT. THEREFORE...WE ELECTED TO UPDATE AN HOUR EARLY TO COVER THE TRENDS. THE LATEST RUC INDICATED SHOWLATERS OF NEAR ZERO ACROSS OUR NORTHERN AREAS. THE SHOWALTER IS INSTABILITY LIFTED FROM THE H850 LEVEL (AROUND 5000 FEET) TO THE H500 LEVEL (AROUND 20,000 FEET). THIS INDICATED PERHAPS A LITTLE INSTABILITY AT THESE LEVELS. IN ADDITION...THE SURFACE BASED CAPES REACHED AROUND 500 J/KG. SINCE THESE INDICES BOTH INDICATE MODEST INSTABILITY...THREW A SLIGHT CHANCE OF THUNDERSTORMS ACROSS OUR ADIRONDACKS ONLY WHERE THE BEST FORCING WILL TAKE PLACE WITH THIS SYSTEM. AGAIN...THE BEST CONCENTRATION OF RAIN WILL BE INTO THE DACKS AND WESTERN MOHAWK VALLEY. THEREAFTER...COMBINATION OF THE DEPARTING UPPER SUPPORT /FORECAST TO SPEED UP TONIGHT/ AND TERRAIN SHOULD BREAK UP THE RAINFALL INTO THE HUDSON VALLEY...MID HUDSON VALLEY AND NW CT AFTER MIDNIGHT. OVERNIGHT LOWS MAINLY INTO THE 50S FOR THE REGION. NO CHANGES MADE TO THESE OVERNIGHT LOWS AT THIS TIME. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... SUNDAY...THE COLD FRONT WILL BE WELL EAST OF THE REGION...HOWEVER...DEEPER CYCLONIC FLOW ALOFT WILL KEEP THE SLIGHT CHANCE FOR SHOWERS /MAINLY TERRAIN/ DURING THE DAY. OTHERWISE...A DEVELOPING BRISK NORTHWESTERLY FLOW WILL EVOLVE AS THE H850 TEMPS DROP BACK TO AT OR JUST BELOW +10C. AS DIURNALLY DRIVEN CLOUDS WILL SET UP MAINLY INTO THE TERRAIN...THIS TOO WILL INFLUENCE THE HIGH TEMPERATURES WHICH SHOULD BE COOLER THAN THOSE OBSERVED SATURDAY. WE WILL FORECAST HIGHS 70-75F FOR VALLEY LOCATIONS AND 60S FOR THE TERRAIN. SUNDAY NIGHT...COLD ADVECTION CONTINUES IN THE WAKE OF THE FRONTAL PASSAGE WITH CANADIAN HIGH PRESSURE RIDGING IN FROM S/SE OF JAMES BAY. H850 TEMPS FALL TO AROUND +8C. CLEARING SKIES AND DIMINISHING N/NW WINDS WILL OCCUR WELL AFTER MIDNIGHT. LOWS WILL RANGE FROM THE LOWER TO M50S IN THE VALLEYS...AND U40S TO L50S OVER THE HILLS AND MTNS. MON-MON NIGHT...THE FLOW ALOFT BECOMES LESS PRONOUNCED AS HEIGHTS SLOWLY RECOVER. MEANWHILE...HIGH PRESSURE AT THE SURFACE BUILDS ACROSS UPSTATE NY. THIS WILL ALLOW FOR A GREAT START TO WEEK WITH DRY CONDITIONS AND CONTINUED LOW HUMIDITY VALUES. SOME HIGH CLOUDS MAY INCREASE FROM THE SOUTH AND WEST FROM A DISTURBANCE TRACKING THROUGH THE LOWER OHIO VALLEY AND OVER THE MID ATLANTIC REGION. AS CONFIDENCE INCREASE WITH THE TRACK OF THIS IMPULSE...THE MON NIGHT PERIOD WAS KEPT DRY BASED ON THE MEDIUM RANGE GUIDANCE TRENDS AND THE STRONG ANTICYCLONE SETTLING OVER UPSTATE NY. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A CHALLENGING EXTENDED PERIOD WILL PREVAIL SINCE THERE WILL CONTINUE TO BE SPLIT FLOW IN THE JETSTREAM. TUESDAY ONE SYSTEM SHOULD STAY SOUTH OF OUR AREA SO WE KEPT THAT DAY DRY WITH WEAK HIGH PRESSURE TO OUR NORTH. WEDNESDAY...ANOTHER WEAK SYSTEM IN THE NORTHERN STREAM WILL APPROACH SO WE HAVE SLIGHT CHANCE OF SHOWERS THAT DAY...INCREASING TO CHANCE POPS (30) BY THURSDAY. IT LOOKS INITIALLY LIKE A WEAK SYSTEM AND ANY RAINFALL WITH IT LOOKS FAIRLY LIGHT FROM THIS VANTAGE POINT. THAT SYSTEM VERY SLOWLY MOVES EAST ALONG A STATIONARY FRONT TO OUR SOUTH. THE LATEST EUROPEAN MODEL INDICATES THIS DISTURBANCE WILL BECOME CUTOFF OVER TO OUR EAST AS WE HEAD INTO THE WEEKEND AND PERHAPS EVEN DEVELOP A SURFACE LOW PRESSURE OFF LONG ISLAND. THE 12Z GFS IS NOT AS AGGRESSIVE WITH THIS SCENARIO. INSTEAD...IT BUILDS A RIDGE TO OUR NORTH...WITH NO REAL LOW PRESSURE...WHICH WOULD BRING DRIER WEATHER. A LOT OF UNCERTAINTIES AT THIS TIME SO FOR NOW...WILL LINGER SLIGHT CHANCE OF POPS THURSDAY AND FRIDAY...INCREASING POPS TO 30 BY SATURDAY SINCE A SURFACE LOW PRESSURE MIGHT DEVELOP TO EAST AND SPREAD SOME SHOWERS OR A STEADY RAIN BACK WEST INTO OUR REGION. TEMPERATURES WILL CONTINUE TO REMAIN SLIGHTLY BELOW NORMAL...ESPECIALLY IF WE END UP WITH A LOT OF CLOUDS DUE AN EASTERLY/NORTHEASTERLY FLOW. FOR NOW...WE WENT MAINLY WITH 70S FOR HIGHS AND MID 50S TO LOWER 60S FOR LOWS THROUGHOUT THE PERIOD. WE MIGHT REACH 80 IN THE VALLEYS ON TUESDAY WITH MORE SUNSHINE EXPECTED ON THAT DAY THAN THE OTHERS. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... EXPECT MAINLY VFR CONDITIONS THROUGHOUT TAF PERIOD. ANY SHOWERS TONIGHT WILL GENERALLY BE LIGHT...TOO LIGHT TO REDUCE VISIBILITY MUCH IF AT ALL. THE CLOUD LAYERS LOOK TO REMAIN ABOVE VFR AS WELL. CLOUDS WILL SHOULD PREVENT ANY RADIATIONAL FOG FROM FORMING. WE JUST WENT WITH THE VCSH FOR NOW AT ALL TAFS STARTING AT 00Z AT KGFL...02Z KALB...03Z KPSF AND 06Z KPOU. WE KEEP THROUGH TOMORROW MORNING ALTHOUGH THE BEST SHOT AT SHOWERS WILL BE OVERNIGHT. VFR CIGS LOOK TO SLOWLY GIVE WAY TO SCATTERED CLOUDS BY MIDDAY. A FRONT WILL CROSS THE TAF SITES EARLY SUNDAY MORNING...WITH A LIGHT S-SW WIND AHEAD OF IT BECOMING VARIABLE UNDER 5KTS TONIGHT. THE WIND WILL TURN W-NW ON SUNDAY MORNING AROUND 10 KTS. WE PLACED GUSTS TO 20KTS AT KPSF AND KALB BY MIDDAY. OUTLOOK... SUN NIGHT-TUE: NO OPERATIONAL IMPACT. NO SIG WX. TUE NIGHT-WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHC SHRA. THURS: MODERATE OPERATIONAL IMPACT. CHC SHRA. && .FIRE WEATHER... LITTLE TO NO FIRE WEATHER CONCERNS AS THERE WILL BE ISOLATED TO SCATTERED SHOWERS TONIGHT. THIS WILL KEEP RH VALUES RATHER HIGH INTO TONIGHT WITH VALUES AT OR ABOVE 80 PERCENT. WHILE THESE SHOWERS DIMINISH TOWARD SUNDAY MORNING...THERE STILL COULD BE A SHOWER OR TWO DURING SUNDAY THAT WILL MAINLY BE CONFINED INTO THE TERRAIN. NORTHWESTERLY WINDS WILL INCREASE DURING SUNDAY WITH GUSTS PERHAPS EXCEEDING 20 MPH. MIN RH VALUES WILL RANGE BETWEEN 45 AND 65 PERCENT. DRIER CONDITIONS WILL OCCUR SUNDAY NIGHT INTO MONDAY WITH DIMINISHING WINDS AND CLEARING SKIES. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE NEXT THREE TO FIVE DAYS. THE LOW PRESSURE SYSTEM AND ITS COLD FRONT WILL BRING MAINLY LIGHT RAINFALL TONIGHT INTO SUNDAY. TOTAL BASIN RAINFALL AMOUNTS WILL MAINLY RANGE FROM A FEW HUNDREDTHS TO A QUARTER OF AN INCH. DRY WEATHER WILL PREVAIL FROM LATE SUNDAY INTO THE MIDDLE OF NEXT WEEK. RIVERS AND STREAMS WILL CONTINUE TO RECEDE BACK TOWARDS MORE NORMAL MID TO LATE AUGUST LEVELS...ESPECIALLY ACROSS WESTERN NEW ENGLAND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...HWJIV/BGM SHORT TERM...BGM LONG TERM...HWJIV AVIATION...HWJIV FIRE WEATHER...BGM/WASULA HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
735 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT AND EAST OF WESTERN NEW ENGLAND BY THE EARLY AFTERNOON ON SUNDAY. THIS FRONT WILL BE ACCOMPANIED WITH THE ISOLATED TO SCATTERED SHOWERS TONIGHT INTO SUNDAY MORNING. CONDITIONS IMPROVE LATER SUNDAY AND INTO EARLY NEXT WEEK AS HIGH PRESSURE RETURNS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 730 PM EDT...RADAR WAS FOLLOWING SCATTERED SHOWERS MAINLY NORTH OF A GLENS FALLS/JOHNSTOWN LINE...MOVING ESE. THESE SHOWERS WERE ENCOUNTERING A PRETTY GOOD LAYER OF DRY AIR AS THEY MOVED SOUTH...SO THE LEADING EDGE APPEARED TO BE WEAKENING. THERE WAS A CLOUD TO GROUND LIGHTNING STRIKE NEAR LAKE ONTARIO. THE LATEST RUC INDICATE SHOWLATERS OF NEAR ZERO ACROSS OUR NORTHERN AREAS. THE SHOWALTER IS INSTABILITY LIFTED FROM THE H850 LEVEL (AROUND 5000 FEET) TO THE H500 LEVEL (AROUND 20,000 FEET). THIS INDICATED PERHAPS A LITTLE INSTABILITY AT THESE LEVELS. IN ADDITION...THE SURFACE BASED CAPES REACHED AROUND 500 J/KG. SINCE THESE INDICES BOTH INDICATE MODEST INSTABILITY...THREW A SLIGHT CHANCE OF THUNDERSTORMS ACROSS OUR ADIRONDACKS ONLY WHERE THE BEST FORCING WILL TAKE PLACE WITH THIS SYSTEM. WE ALSO TOUCHED UP THE POPS TRIMMING THEM INITIALLY THEN INCREASING THEM TOWARD MIDNIGHT ACROSS OUR REGION. OVERALL THE FORECAST LOOKED FINE. AGAIN...THE BEST CONCENTRATION OF RAIN WILL BE INTO THE DACKS AND WESTERN MOHAWK VALLEY. THEREAFTER...COMBINATION OF THE DEPARTING UPPER SUPPORT /FORECAST TO SPEED UP TONIGHT/ AND TERRAIN SHOULD BREAK UP THE RAINFALL INTO THE HUDSON VALLEY...MID HUDSON VALLEY AND NW CT AFTER MIDNIGHT. OVERNIGHT LOWS MAINLY INTO THE 50S FOR THE REGION. NO CHANGES MADE TO THESE AT THIS TIME. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... SUNDAY...THE COLD FRONT WILL BE WELL EAST OF THE REGION...HOWEVER...DEEPER CYCLONIC FLOW ALOFT WILL KEEP THE SLIGHT CHANCE FOR SHOWERS /MAINLY TERRAIN/ DURING THE DAY. OTHERWISE...A DEVELOPING BRISK NORTHWESTERLY FLOW WILL EVOLVE AS THE H850 TEMPS DROP BACK TO AT OR JUST BELOW +10C. AS DIURNALLY DRIVEN CLOUDS WILL SET UP MAINLY INTO THE TERRAIN...THIS TOO WILL INFLUENCE THE HIGH TEMPERATURES WHICH SHOULD BE COOLER THAN THOSE OBSERVED SATURDAY. WE WILL FORECAST HIGHS 70-75F FOR VALLEY LOCATIONS AND 60S FOR THE TERRAIN. SUNDAY NIGHT...COLD ADVECTION CONTINUES IN THE WAKE OF THE FRONTAL PASSAGE WITH CANADIAN HIGH PRESSURE RIDGING IN FROM S/SE OF JAMES BAY. H850 TEMPS FALL TO AROUND +8C. CLEARING SKIES AND DIMINISHING N/NW WINDS WILL OCCUR WELL AFTER MIDNIGHT. LOWS WILL RANGE FROM THE LOWER TO M50S IN THE VALLEYS...AND U40S TO L50S OVER THE HILLS AND MTNS. MON-MON NIGHT...THE FLOW ALOFT BECOMES LESS PRONOUNCED AS HEIGHTS SLOWLY RECOVER. MEANWHILE...HIGH PRESSURE AT THE SURFACE BUILDS ACROSS UPSTATE NY. THIS WILL ALLOW FOR A GREAT START TO WEEK WITH DRY CONDITIONS AND CONTINUED LOW HUMIDITY VALUES. SOME HIGH CLOUDS MAY INCREASE FROM THE SOUTH AND WEST FROM A DISTURBANCE TRACKING THROUGH THE LOWER OHIO VALLEY AND OVER THE MID ATLANTIC REGION. AS CONFIDENCE INCREASE WITH THE TRACK OF THIS IMPULSE...THE MON NIGHT PERIOD WAS KEPT DRY BASED ON THE MEDIUM RANGE GUIDANCE TRENDS AND THE STRONG ANTICYCLONE SETTLING OVER UPSTATE NY. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A CHALLENGING EXTENDED PERIOD WILL PREVAIL SINCE THERE WILL CONTINUE TO BE SPLIT FLOW IN THE JETSTREAM. TUESDAY ONE SYSTEM SHOULD STAY SOUTH OF OUR AREA SO WE KEPT THAT DAY DRY WITH WEAK HIGH PRESSURE TO OUR NORTH. WEDNESDAY...ANOTHER WEAK SYSTEM IN THE NORTHERN STREAM WILL APPROACH SO WE HAVE SLIGHT CHANCE OF SHOWERS THAT DAY...INCREASING TO CHANCE POPS (30) BY THURSDAY. IT LOOKS INITIALLY LIKE A WEAK SYSTEM AND ANY RAINFALL WITH IT LOOKS FAIRLY LIGHT FROM THIS VANTAGE POINT. THAT SYSTEM VERY SLOWLY MOVES EAST ALONG A STATIONARY FRONT TO OUR SOUTH. THE LATEST EUROPEAN MODEL INDICATES THIS DISTURBANCE WILL BECOME CUTOFF OVER TO OUR EAST AS WE HEAD INTO THE WEEKEND AND PERHAPS EVEN DEVELOP A SURFACE LOW PRESSURE OFF LONG ISLAND. THE 12Z GFS IS NOT AS AGGRESSIVE WITH THIS SCENARIO. INSTEAD...IT BUILDS A RIDGE TO OUR NORTH...WITH NO REAL LOW PRESSURE...WHICH WOULD BRING DRIER WEATHER. A LOT OF UNCERTAINTIES AT THIS TIME SO FOR NOW...WILL LINGER SLIGHT CHANCE OF POPS THURSDAY AND FRIDAY...INCREASING POPS TO 30 BY SATURDAY SINCE A SURFACE LOW PRESSURE MIGHT DEVELOP TO EAST AND SPREAD SOME SHOWERS OR A STEADY RAIN BACK WEST INTO OUR REGION. TEMPERATURES WILL CONTINUE TO REMAIN SLIGHTLY BELOW NORMAL...ESPECIALLY IF WE END UP WITH A LOT OF CLOUDS DUE AN EASTERLY/NORTHEASTERLY FLOW. FOR NOW...WE WENT MAINLY WITH 70S FOR HIGHS AND MID 50S TO LOWER 60S FOR LOWS THROUGHOUT THE PERIOD. WE MIGHT REACH 80 IN THE VALLEYS ON TUESDAY WITH MORE SUNSHINE EXPECTED ON THAT DAY THAN THE OTHERS. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... EXPECT MAINLY VFR CONDITIONS THROUGHOUT TAF PERIOD. ANY SHOWERS TONIGHT WILL GENERALLY BE LIGHT...TOO LIGHT TO REDUCE VISIBILITY MUCH IF AT ALL. THE CLOUD LAYERS LOOK TO REMAIN ABOVE VFR AS WELL. CLOUDS WILL SHOULD PREVENT ANY RADIATIONAL FOG FROM FORMING. WE JUST WENT WITH THE VCSH FOR NOW AT ALL TAFS STARTING AT 00Z AT KGFL...02Z KALB...03Z KPSF AND 06Z KPOU. WE KEEP THROUGH TOMORROW MORNING ALTHOUGH THE BEST SHOT AT SHOWERS WILL BE OVERNIGHT. VFR CIGS LOOK TO SLOWLY GIVE WAY TO SCATTERED CLOUDS BY MIDDAY. A FRONT WILL CROSS THE TAF SITES EARLY SUNDAY MORNING...WITH A LIGHT S-SW WIND AHEAD OF IT BECOMING VARIABLE UNDER 5KTS TONIGHT. THE WIND WILL TURN W-NW ON SUNDAY MORNING AROUND 10 KTS. WE PLACED GUSTS TO 20KTS AT KPSF AND KALB BY MIDDAY. OUTLOOK... SUN NIGHT-TUE: NO OPERATIONAL IMPACT. NO SIG WX. TUE NIGHT-WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHC SHRA. THURS: MODERATE OPERATIONAL IMPACT. CHC SHRA. && .FIRE WEATHER... LITTLE TO NO FIRE WEATHER CONCERNS AS THERE WILL BE ISOLATED TO SCATTERED SHOWERS TONIGHT. THIS WILL KEEP RH VALUES RATHER HIGH INTO TONIGHT WITH VALUES AT OR ABOVE 80 PERCENT. WHILE THESE SHOWERS DIMINISH TOWARD SUNDAY MORNING...THERE STILL COULD BE A SHOWER OR TWO DURING SUNDAY THAT WILL MAINLY BE CONFINED INTO THE TERRAIN. NORTHWESTERLY WINDS WILL INCREASE DURING SUNDAY WITH GUSTS PERHAPS EXCEEDING 20 MPH. MIN RH VALUES WILL RANGE BETWEEN 45 AND 65 PERCENT. DRIER CONDITIONS WILL OCCUR SUNDAY NIGHT INTO MONDAY WITH DIMINISHING WINDS AND CLEARING SKIES. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE NEXT THREE TO FIVE DAYS. THE LOW PRESSURE SYSTEM AND ITS COLD FRONT WILL BRING MAINLY LIGHT RAINFALL TONIGHT INTO SUNDAY. TOTAL BASIN RAINFALL AMOUNTS WILL MAINLY RANGE FROM A FEW HUNDREDTHS TO A QUARTER OF AN INCH. DRY WEATHER WILL PREVAIL FROM LATE SUNDAY INTO THE MIDDLE OF NEXT WEEK. RIVERS AND STREAMS WILL CONTINUE TO RECEDE BACK TOWARDS MORE NORMAL MID TO LATE AUGUST LEVELS...ESPECIALLY ACROSS WESTERN NEW ENGLAND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...HWJIV/BGM SHORT TERM...BGM LONG TERM...HWJIV AVIATION...HWJIV FIRE WEATHER...BGM/WASULA HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS MIAMI FL
313 PM EDT FRI AUG 15 2014 .DISCUSSION... AS OF 1830Z...VERY ACTIVE CONVECTION ACROSS THE ATLANTIC COAST AND THE ADJACENT ATLANTIC WATERS. VERY ACTIVE THUNDERSTORMS EXTEND FROM NORTHEAST MIAMI DADE NORTHWARD THROUGH EASTERN BROWARD AND PALM BEACH COUNTIES. THE LATEST HRRR MESO-SCALE MODEL GUIDANCE WHICH INITIALIZED GENERALLY WELL ON THIS CONVECTION INDICATES THIS ACTIVITY STARTING TO DISSIPATE AROUND 22Z. BUT AS ALWAYS WITH EXISTING OUTFLOW BOUNDARIES ADDITIONAL CONVECTION COULD LINGER INTO THE EARLY EVENING HOURS WITH THE CURRENT FORECAST INDICATING ACTIVE CONVECTION WITH NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE EASTERN HALF OF THE PENINSULA THROUGH 00Z THIS EVENING. THE LATEST MODEL GUIDANCE INDICATES SOME RELATIVELY DRIER AIR FORECAST TO MOVE NORTHWARD INTO THE FLORIDA STRAITS TONIGHT INTO SATURDAY. HOWEVER...THE GUIDANCE INDICATES THAT IT MAY NOT MAKE IT FAR ENOUGH NORTHWARD ON SATURDAY SUCH THAT LINGERING DEEP MOISTURE OVER MOST OF THE PENINSULA AND ADJACENT WATERS COULD LEAD TO ADDITIONAL AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE REGION WITH THE SATURDAY FORECAST INDICATING THE GREATEST COVERAGE ACROSS THE INTERIOR ALTHOUGH SCATTERED ACTIVITY IS FORECAST FOR THE GULF AND ATLANTIC COAST METRO AREAS. BY SUNDAY THE GUIDANCE INDICATES THAT THE DRIER AIR IS FORECAST TO CONTINUE MOVING NORTH WITH A CONSIDERABLE REDUCTION ACROSS THE REGION IN SHOWERS/THUNDERSTORMS WITH MAINLY THE INTERIOR REGIONS FORECAST TO HAVE SCATTERED ACTIVITY. THERE IS GUIDANCE SUGGESTING THAT SOME DUST ASSOCIATED WITH THE SAHARAN AIR LAYER COULD ENTER THE REGION LATE SATURDAY INTO SUNDAY THEN MOVE ACROSS THE REGION LATE SUNDAY AND PERSIST INTO EARLY NEXT WEEK. SO THERE MAY BE NOTICEABLY HAZY SKIES SUNDAY INTO EARLY NEXT WEEK. && .MARINE... LIGHT SOUTH TO SOUTHWEST WINDS ARE FORECAST ACROSS THE REGIONAL WATERS TONIGHT THROUGH SATURDAY. BY SUNDAY WINDS ARE FORECAST TO BECOME EAST TO SOUTHEAST WHILE REMAINING AROUND OR BELOW 10 KNOTS AND PERSISTING INTO EARLY NEXT WEEK. REGIONAL SEAS ARE FORECAST TO BE 2 FEET OR LESS THROUGH THE WEEKEND INTO AT LEAST EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 90 77 90 78 / 60 30 50 20 FORT LAUDERDALE 91 79 91 81 / 60 20 50 20 MIAMI 91 78 90 80 / 60 20 40 10 NAPLES 90 78 90 78 / 50 20 30 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...21/KM LONG TERM....60/BD
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
910 AM EDT FRI AUG 15 2014 .DISCUSSION... CURRENT-THIS AFTERNOON...THE 8AM/12Z SOUNDINGS INDICATED THAT THE PRECIPITABLE WATER VALUES FOR CENTRAL FLORIDA CONTINUE TO ABOVE 2 INCHES MEANING A VERY MOIST ATMOSPHERE. NOTED THAT THE 15/06Z GFS POSITIONED THE 1000-500MB RELATIVE HUMIDITY A LITTLE FURTHER SOUTH THAN PREVIOUS DAYS. BOTH THE MORNING SOUNDINGS FOR CENTRAL AND SOUTH FLORIDA AND THE VERTICAL WIND PROFILER(S) AT THE SPACE CENTER SHOW DEEP LAYER ...SURFACE TO 500MB...WESTERLY FLOW. THE TROUGHING ASSOCIATED WITH AN UPPER LEVEL LOW OVER CANADA EXTENDS OVER THE EASTERN THIRD OF THE U.S. AND INTO THE NORTHEAST GULF MEXICO CONTINUES TO KEEP THE LOW AND MID LEVEL RIDGE SUPPRESSED TO THE SOUTH OVER THE CENTRAL BAHAMA ISLAND SOUTH FLORIDA AND THE FLORIDA STRAIT FOR ANOTHER DAY. THE CIRRUS AND MID LEVEL CLOUDINESS FROM LATE NIGHT AND EARLY MORNING STORMS STREAMING OVERHEAD MAY DELAY DAYTIME HEATING FOR THE MORNING AND DELAY ONSET OF HIGHER COVERAGE OF STORMS FOR THE AFTERNOON. TIMING OF THE WEATHER FOR THE REST OF THE DAY LOOKS REASONABLE BASED ON TRENDS OBSERVED FOR THE PAST 2 TO 3 DAYS. ZONE UPDATE WILL ADDRESS CHANGES TO THE VARIOUS WIND GRIDS AND MAX TEMPERATURES FOR THIS AFTERNOON IF THE CIRRUS AND MID LEVEL CLOUDINESS LOOKS LIKE IT WILL PLAY A SIGNIFICANT ROLE IN HINDERING DAYTIME HEATING. PREVIOUS ZONES DISCUSSION TODAY...NOT MUCH CHANGE IN THE PATTERN FROM YESTERDAY WITH A STALLED FRONT ACROSS SE GA INTO THE FL PANHANDLE. LOW-MID LVL WSW WINDS WILL CONTINUE WITH DEEP MOISTURE OVER THE AREA AS PRECIPITABLE WATER VALUES ARE FORECAST FROM FROM 2.0 TO 2.2 INCHES. SHORT RANGE MODELS ALSO INDICATE MID LVL IMPULSES WILL TRAVERSE THE NRN/CENTRAL FL PENINSULA TODAY LEADING TO SOME CONVECTIVE ORGANIZATION AS STORMS MAKE THEIR WAY FROM THE WEST TO EAST ACROSS THE AREA. HRRR AND SPC WRF RUN THIS MORNING INDICATE CONVECTION DEVELOPING TO OUR WEST BY LATE MORNING AND MOVING TOWARD THE ORLANDO METRO BY EARLY AFTERNOON. STORMS SHOULD THEN APPROACH CSTL VOLUSIA AND BREVARD COUNTY BY MID AFTERNOON AND TOWARD THE TREASURE COAST INTO THE MID TO LATE AFTERNOON HOURS. THE EAST COAST SEA BREEZE WILL LIKELY DEVELOP FROM VERO BEACH SOUTH TO STUART AND INCH ONLY SLOWLY INLAND FROM THE COAST. STORMS WILL MOVE EAST AROUND 15 MPH. THE PRIMARY THUNDERSTORM HAZARDS WILL BE LOCALLY HEAVY RAIN...GUSTY WINDS AND FREQUENT LIGHTNING. HIGHS WILL BE MAINLY AROUND 90 TO THE LOWER 90S. TONIGHT...THERE WILL BE A CHANCE FOR EARLY EVENING STORMS POSSIBLY MORE CONCENTRATED NEAR THE TREASURE COAST WHERE STORMS MAY LINGER FROM LATE AFTN INTO THE EVENING. SW LOW LVL FLOW SHOULD PUSH MOST OF THE ACTIVITY INTO THE ATLC BY LATE EVENING. LOWS WILL BE IN THE LOWER TO MID 70S. SAT...NOT MUCH CHANGE AS DEEP MOISTURE (PWATS AROUND 2 INCHES) IS PROGGED TO CONTINUE ESPECIALLY ACROSS NORTHERN HALF OF FA. FAST W/SW FLOW ALONG WITH A MID LEVEL IMPULSE SHOULD PRODUCE AN EARLY START TO SHOWERS AND STORMS DURING THE MORNING ESP NORTH OF ORLANDO. SHOULD SEE AN AFTERNOON SEA BREEZE DEVELOP WITH SOME INLAND PENETRATION ACROSS MARTIN AND ST LUCIE COUNTIES BUT IT IS NOT EXPECTED TO PUSH VERY FAR INLAND NORTH OF THE CAPE. HIGHEST STORM CHANCES APPEAR TO BE LATE IN THE AFTN ASSOCD WITH A SEA BREEZE COLLISION EXTENDING FROM COASTAL VOLUSIA SOUTHWARD TO LAKE OKEECHOBEE. HAVE DRAWN 50 POPS NORTH AND 40 POPS SOUTH. HIGH TEMPERATURES AROUND 90/LWR 90S NEAR THE COAST TO LWR-MID 90S OVER THE INTERIOR. LOWS WILL BE IN THE 70S. SUN...THE LOW LVL RIDGE AXIS WILL LIFT NORTHWARD T0 LAKE OKEECHOBEE. THIS WILL REDUCE THE LOW LVL WESTERLY FLOW ACROSS THE SOUTH WHICH WILL ALLOW AN EARLIER ONSET OF THE SEA BREEZE SOUTH OF THE CAPE. RAIN CHANCES WILL BE LOWER DUE TO DECREASING MOISTURE LEVELS AND LITTLE UPPER SUPPORT. FOCUS FOR STORMS WILL BE OVER THE INTERIOR WITH PUSH BACK TO THE EAST COAST BUT COVERAGE LOOKS LOWER THAN PREVIOUS DAYS AT 30 TO 40 PERCENT. INTERIOR SECTIONS WILL BE A DEGREE OR TWO HOTTER GIVEN MORE SUN AND LESS COVERAGE OF STORMS. MON-THU...THE GFS AND ECMWF SHOW A DRYING TREND WITH DECREASING MOISTURE IN THE H8-H5 LAYER. HAVE LOWERED RAIN CHANCES TO 20 PCT TUE-WED AND 30 PERCENT THU. THIS MEANS HIGH TEMPERATURES WILL BE HOT...SOLIDLY IN THE MID 90S INTERIOR AND POSSIBLY VOLUSIA COAST...LOWER 90S SOUTH OF THE CAPE. && .AVIATION... CURRENT...FIRST ROUND OF STORMS PUSHED THROUGH THE WESTERN TAF SITES BY 12. NEXT ROUND OF SCATTERED STORMS MOVING ACROSS THE EASTERN GULF AND WEST COAST OF FLORIDA FROM CEDAR KEY TO PUNTA GORDA PER RADAR. TEMPO MVFR CEILINGS AND VISIBILITIES ALL DAY AS STORMS MOVE WEST TO EAST AT 15 KNOTS. STRONGER STORMS POSSIBLE AT THE COAST MELBOURNE SOUTH AS EXISTING STORMS INTERACT WITH ANY SEA BREEZES TRYING FORM AT THE COAST. PREVIOUS AVIATION DISCUSSION SCT-NMRS TSRA WILL DVLP AND MOVE EASTWARD ACROSS E CENTRAL FL THIS AFTN. EXPECT CONVECTION TO AFFECT NRN INTERIOR TERMINALS INCLUDING KMCO FROM 18Z-20Z...WITH STORMS THEN PUSHING TWD THE KDAB-KMLB BY 18Z-21Z. STORMS MAY MOVE IN FROM THE WEST AND DVLP NEAR THE EAST COAST SEA BRZ BOUNDARY FROM 19Z-23Z FROM KVRB-KSUA. MAINLY VFR WX AFT 01Z. && .MARINE... CURRENT-THIS AFTERNOON...NOAA BUOYS 009 AND 010 RECORDING SOUTHWEST WINDS THAT WERE AVERAGING 10 TO 15 KNOTS AND 2 TO 3 FOOT SEAS. CMAN AND SCRIPPS BUOYS WERE RECORDING SOUTHWEST WINDS TO 10 KNOTS AND 1 FOOT SEAS. SURFACE RIDGE AXIS REMAINS SOUTH OF THE AREA THUS SOUTHWEST FLOW CONTINUES. ANY SEA BREEZE SHOULD FORM AT THE COAST SEBASTIAN INLET SOUTH. INCREASING COVERAGE OF AFTERNOON STORMS MOVING WEST TO EAST OVER THE MAINLAND LAKES...RIVERS AND CROSSING THE HALIFAX RIVER AND THE MOSQUITO INDIAN RIVER LAGOONS INTO THE NEARSHORE WATERS LATER TODAY. MORNING UPDATE TO THE MARINE FORECAST WILL BE TO THE WIND GRIDS. PREVIOUS MARINE DISCUSSION SW WINDS TO AROUND 10 KNOTS WILL BUILD SEAS TO 2-3 FT OFFSHORE BUT STILL STAY NEAR 1-2 FT ALONG THE IMMEDIATE COAST WITH OFFSHORE FLOW. EXPECT SHOWERS AND LIGHTNING STORMS TO AFFECT THE INTRACOASTAL AND NEAR SHORE ATLANTIC WATERS FROM 2 PM TO 8 PM WITH STRONGER STORMS CAPABLE OF PRODUCING WINDS ABOVE 35 KNOTS. WEEKEND...SURFACE RIDGE AXIS IS FORECAST TO REMAIN SOUTH OF OUR COASTAL WATERS SAT THEN SLOWLY LIFT NORTH TO LAKE OKEECHOBEE SUNDAY. PERSISTENT WEST TO SOUTHWEST WINDS 10 TO 15 KNOTS SAT WILL BRING SCATTERED LIGHTNING STORMS OFF THE COAST DURING THE AFTN/EVE ALONG WITH GUSTY WINDS. OFFSHORE FLOW WEAKENS SUNDAY SOUTH OF SEBASTIAN INLET WITH LESS STORM ACTIVITY ABLE TO REACH THE TREASURE COAST. BUT STRONGER OFFSHORE STEERING FLOW WILL BRING SCATTERED STORMS OFFSHORE VOLUSIA AND BREVARD COUNTIES AGAIN LATE SUNDAY. MON-TUE...SOUTH TO SOUTHWEST FLOW WILL TURN SE NEAR THE COAST IN A SEA BREEZE. SOME DRIER AIR SHOULD LIMIT COVERAGE OF STORMS OVER THE PENINSULA BY TUE BUT THERE WILL BE A THREAT FOR OFFSHORE MOVING STORMS NORTH OF SEBASTIAN LATE MONDAY. && .PRELIMINARY POINT TEMPS/POPS... DAB 90 73 92 75 / 60 30 50 30 MCO 91 74 94 75 / 60 30 50 20 MLB 90 75 92 75 / 60 30 50 30 VRB 90 74 92 75 / 60 30 40 20 LEE 90 75 93 77 / 60 30 50 20 SFB 92 75 95 77 / 60 30 50 20 ORL 91 75 94 78 / 60 30 50 20 FPR 90 74 92 75 / 60 30 40 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ IMPACT WX...LASCODY PUBLIC SV...GLITTO FORECASTS...WIMMER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
424 AM EDT FRI AUG 15 2014 .DISCUSSION... TODAY...NOT MUCH CHANGE IN THE PATTERN FROM YESTERDAY WITH A STALLED FRONT ACROSS SE GA INTO THE FL PANHANDLE. LOW-MID LVL WSW WINDS WILL CONTINUE WITH DEEP MOISTURE OVER THE AREA AS PRECIPITABLE WATER VALUES ARE FORECAST FROM FROM 2.0 TO 2.2 INCHES. SHORT RANGE MODELS ALSO INDICATE MID LVL IMPULSES WILL TRAVERSE THE NRN/CENTRAL FL PENINSULA TODAY LEADING TO SOME CONVECTIVE ORGANIZATION AS STORMS MAKE THEIR WAY FROM THE WEST TO EAST ACROSS THE AREA. HRRR AND SPC WRF RUN THIS MORNING INDICATE CONVECTION DEVELOPING TO OUR WEST BY LATE MORNING AND MOVING TOWARD THE ORLANDO METRO BY EARLY AFTERNOON. STORMS SHOULD THEN APPROACH CSTL VOLUSIA AND BREVARD COUNTY BY MID AFTERNOON AND TOWARD THE TREASURE COAST INTO THE MID TO LATE AFTERNOON HOURS. THE EAST COAST SEA BREEZE WILL LIKELY DEVELOP FROM VERO BEACH SOUTH TO STUART AND INCH ONLY SLOWLY INLAND FROM THE COAST. STORMS WILL MOVE EAST AROUND 15 MPH. THE PRIMARY THUNDERSTORM HAZARDS WILL BE LOCALLY HEAVY RAIN...GUSTY WINDS AND FREQUENT LIGHTNING. HIGHS WILL BE MAINLY AROUND 90 TO THE LOWER 90S. TONIGHT...THERE WILL BE A CHANCE FOR EARLY EVENING STORMS POSSIBLY MORE CONCENTRATED NEAR THE TREASURE COAST WHERE STORMS MAY LINGER FROM LATE AFTN INTO THE EVENING. SW LOW LVL FLOW SHOULD PUSH MOST OF THE ACTIVITY INTO THE ATLC BY LATE EVENING. LOWS WILL BE IN THE LOWER TO MID 70S. SAT...NOT MUCH CHANGE AS DEEP MOISTURE (PWATS AROUND 2 INCHES) IS PROGGED TO CONTINUE ESPECIALLY ACROSS NORTHERN HALF OF FA. FAST W/SW FLOW ALONG WITH A MID LEVEL IMPULSE SHOULD PRODUCE AN EARLY START TO SHOWERS AND STORMS DURING THE MORNING ESP NORTH OF ORLANDO. SHOULD SEE AN AFTERNOON SEA BREEZE DEVELOP WITH SOME INLAND PENETRATION ACROSS MARTIN AND ST LUCIE COUNTIES BUT IT IS NOT EXPECTED TO PUSH VERY FAR INLAND NORTH OF THE CAPE. HIGHEST STORM CHANCES APPEAR TO BE LATE IN THE AFTN ASSOCD WITH A SEA BREEZE COLLISION EXTENDING FROM COASTAL VOLUSIA SOUTHWARD TO LAKE OKEECHOBEE. HAVE DRAWN 50 POPS NORTH AND 40 POPS SOUTH. HIGH TEMPERATURES AROUND 90/LWR 90S NEAR THE COAST TO LWR-MID 90S OVER THE INTERIOR. LOWS WILL BE IN THE 70S. SUN...THE LOW LVL RIDGE AXIS WILL LIFT NORTHWARD T0 LAKE OKEECHOBEE. THIS WILL REDUCE THE LOW LVL WESTERLY FLOW ACROSS THE SOUTH WHICH WILL ALLOW AN EARLIER ONSET OF THE SEA BREEZE SOUTH OF THE CAPE. RAIN CHANCES WILL BE LOWER DUE TO DECREASING MOISTURE LEVELS AND LITTLE UPPER SUPPORT. FOCUS FOR STORMS WILL BE OVER THE INTERIOR WITH PUSH BACK TO THE EAST COAST BUT COVERAGE LOOKS LOWER THAN PREVIOUS DAYS AT 30 TO 40 PERCENT. INTERIOR SECTIONS WILL BE A DEGREE OR TWO HOTTER GIVEN MORE SUN AND LESS COVERAGE OF STORMS. MON-THU...THE GFS AND ECMWF SHOW A DRYING TREND WITH DECREASING MOISTURE IN THE H8-H5 LAYER. HAVE LOWERED RAIN CHANCES TO 20 PCT TUE-WED AND 30 PERCENT THU. THIS MEANS HIGH TEMPERATURES WILL BE HOT...SOLIDLY IN THE MID 90S INTERIOR AND POSSIBLY VOLUSIA COAST...LOWER 90S SOUTH OF THE CAPE. && .AVIATION... SCT-NMRS TSRA WILL DVLP AND MOVE EASTWARD ACROSS E CENTRAL FL THIS AFTN. EXPECT CONVECTION TO AFFECT NRN INTERIOR TERMINALS INCLUDING KMCO FROM 18Z-20Z...WITH STORMS THEN PUSHING TWD THE KDAB-KMLB BY 18Z-21Z. STORMS MAY MOVE IN FROM THE WEST AND DVLP NEAR THE EAST COAST SEA BRZ BOUNDARY FROM 19Z-23Z FROM KVRB-KSUA. MAINLY VFR WX AFT 01Z. && .MARINE... SW WINDS TO AROUND 10 KNOTS WILL BUILD SEAS TO 2-3 FT OFFSHORE BUT STILL STAY NEAR 1-2 FT ALONG THE IMMEDIATE COAST WITH OFFSHORE FLOW. EXPECT SHOWERS AND LIGHTNING STORMS TO AFFECT THE INTRACOASTAL AND NEAR SHORE ATLANTIC WATERS FROM 2 PM TO 8 PM WITH STRONGER STORMS CAPABLE OF PRODUCING WINDS ABOVE 35 KNOTS. WEEKEND...SURFACE RIDGE AXIS IS FORECAST TO REMAIN SOUTH OF OUR COASTAL WATERS SAT THEN SLOWLY LIFT NORTH TO LAKE OKEECHOBEE SUNDAY. PERSISTENT WEST TO SOUTHWEST WINDS 10 TO 15 KNOTS SAT WILL BRING SCATTERED LIGHTNING STORMS OFF THE COAST DURING THE AFTN/EVE ALONG WITH GUSTY WINDS. OFFSHORE FLOW WEAKENS SUNDAY SOUTH OF SEBASTIAN INLET WITH LESS STORM ACTIVITY ABLE TO REACH THE TREASURE COAST. BUT STRONGER OFFSHORE STEERING FLOW WILL BRING SCATTERED STORMS OFFSHORE VOLUSIA AND BREVARD COUNTIES AGAIN LATE SUNDAY. MON-TUE...SOUTH TO SOUTHWEST FLOW WILL TURN SE NEAR THE COAST IN A SEA BREEZE. SOME DRIER AIR SHOULD LIMIT COVERAGE OF STORMS OVER THE PENINSULA BY TUE BUT THERE WILL BE A THREAT FOR OFFSHORE MOVING STORMS NORTH OF SEBASTIAN LATE MONDAY. && .PRELIMINARY POINT TEMPS/POPS... DAB 90 73 92 75 / 60 30 50 30 MCO 91 74 94 75 / 60 30 50 20 MLB 90 75 92 75 / 60 30 50 30 VRB 90 74 92 75 / 60 30 40 20 LEE 90 75 93 77 / 60 30 50 20 SFB 92 75 95 77 / 60 30 50 20 ORL 91 75 94 78 / 60 30 50 20 FPR 90 74 92 75 / 60 30 40 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM...VOLKMER LONG TERM....KELLY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
500 PM CDT FRI AUG 15 2014 .DISCUSSION... 254 PM CDT THE MAIN FORECAST CONCERNS WILL CONTINUE TO FOCUS ON THE CHANCES OF THUNDERSTORMS AND THE POSSIBILITY OF HEAVY RAIN ACROSS PORTIONS OF MY AREA THROUGH THE WEEKEND. COOL SURFACE HIGH PRESSURE CONTINUES TO SHIFT EAST-SOUTHEASTWARD OVER THE OHIO VALLEY EARLY THIS AFTERNOON. THIS IS PRODUCING ANOTHER FABULOUS WEATHER DAY ACROSS THE REGION THIS AFTERNOON WITH TEMPERATURES PRIMARILY IN THE MID TO UPPER 70S. HOWEVER...ATTENTION IS BEGINNING TO FOCUS ON THE SYSTEM TO OUR WEST...WHICH IS ALREADY PUSHING SOME HIGHER LEVEL CLOUDINESS INTO MY SOUTHWESTERN AREAS. WATER VAPOR IMAGERY EARLY THIS AFTERNOON INDICATES THE PRESENCE OF A COUPLE OF MID/UPPER LEVEL DISTURBANCES ACROSS THE PLAINS. THE FIRST IS LOCATED OVER THE WESTERN DAKOTAS...WITH THE SECOND OVER THE NEBRASKA-KANSAS BOARDER. HOWEVER...IT IS THE SOUTHERNMOST DISTURBANCE THAT IS THE MAIN FOCUS FOR THE WEATHER EXPECTED MUCH OF THIS WEEKEND ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH TRACKING THIS DISTURBANCE SLOWLY EASTWARD ACROSS SOUTHERN IOWA TONIGHT...THEN EAST-SOUTHEASTWARD ACROSS CENTRAL ILLINOIS BY SUNDAY MORNING. THE GFS AND ECMWF ARE FAVORED WITH THE HANDLING OF THE SYSTEM THROUGH THE WEEKEND. CONVECTIVE ACTIVITY WILL LIKELY FIRE UP DOWNSTREAM OF THE SOUTHERN NEBRASKA DISTURBANCE TONIGHT...NAMELY ACROSS PORTIONS OF SOUTHERN IOWA...MISSOURI AND PERHAPS ACROSS FAR WESTERN ILLINOIS ALONG THE NOSE OF A DEVELOPING SOUTH-SOUTHWESTERLY LOW LEVEL JET. THE REMNANTS OF SOME OF THIS ACTIVITY WILL TRY TO MOVE EASTWARD ACROSS THE AREA SATURDAY MORNING. HOWEVER...IT APPEARS THIS ACTIVITY WILL LIKELY WEAKEN CONSIDERABLY WITH EASTWARD EXTENT DURING THE MORNING AS IT MOVES AWAY FROM THE BETTER FORCING AND INSTABILITY. AS SUCH...IT APPEARS THE THREAT FOR THUNDERSTORMS WILL BE LOW ACROSS MUCH OF NORTHEASTERN ILLINOIS AND INTO INDIANA...WITH POSSIBLY ONLY SOME SHOWERS VOID OF THUNDER POSSIBLE. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON AND NIGHT AS THE MAIN UPPER SYSTEM MOVES FROM SOUTHEASTERN IOWA OVER CENTRAL ILLINOIS. HOWEVER...AGAIN IT APPEARS THE MAIN THREAT OF THUNDER WILL REMAIN ALONG AND SOUTH OF INTERSTATE 80 TO THE EAST OF THE TRACK OF THE MID LEVEL WAVE. THERE IS A THREAT FOR SOME VERY HEAVY RAINFALL WITH THESE STORMS ON SATURDAY/SATURDAY NIGHT ACROSS CENTRAL ILLINOIS GIVEN PWATS COULD BE IN EXCESS OF 2 INCHES AND WARM CLOUD DEPTHS IN EXCESS OF 13,000 FEET. THIS THREAT WILL NEED TO BE WATCHED...BUT AT THIS TIME IT APPEARS THE PRIMARILY THREAT FOR THIS HEAVY RAINFALL COULD REMAIN JUST OUTSIDE MY AREA. A COLD FRONT IS ALSO EXPECTED TO DROP DOWN LAKE MICHIGAN LATE SATURDAY. THIS COLD FRONT SHOULD SHIFT SOUTHWARD ACROSS NORTHERN ILLINOIS BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING. ONCE THIS FRONT PUSHES THROUGH...ONSHORE FLOW WILL PREVAIL ACROSS NORTHEASTERN ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA. THIS SHOULD KEEP MUCH OF NORTHERN ILLINOIS DRY BUT CLOUDY ON SUNDAY. AS A RESULT...I HAVE DROPPED POPS ACROSS MUCH OF NORTHERN ILLINOIS ON SUNDAY. HOWEVER...THE EFFECTS OF THE MID LEVEL SYSTEM WILL STILL POSSIBLY LEAD TO ADDITIONAL THUNDERSTORMS SUNDAY...PRIMARILY ACROSS MY EAST CENTRAL ILLINOIS AND NORTHWESTERN INDIANA COUNTIES. HEAVY RAINFALL WILL AGAIN BE A THREAT WITH THESE STORMS. THINGS FINALLY QUITE DOWN AREA-WIDE FOR A SHORT PERIOD LATE MONDAY. HOWEVER...THE WEATHER PATTERN FROM MID TO LATE THIS COMING WEEK LOOKS TO BE A WARMER AND ACTIVE AT TIMES. THE UPPER LOW/TROUGH CURRENT IN PLACE ACROSS THE PACIFIC NORTHWEST IS PROGGED TO SHIFT EASTWARD ACROSS THE UPPER MIDWEST BY TUESDAY. THIS WILL BRING OUR NEXT CHANCE OF SHOWERS AND STORMS TO AREA...ALONG WITH WARMER TEMPERATURES. ADDITIONAL WAVES OF STORMS ARE POSSIBLE LATER IN THE WEEK AS WELL WITH THE LIKELIHOOD OF THE MID/UPPER LEVEL PATTERN REMAINING DISTURBED ACROSS THE NORTHERN HALF OF THE COUNTRY. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * CHANCE FOR BRIEF SOUTHEAST WINDS EARLY THIS EVE BUT SPEEDS SHOULD BE UNDER 10 KT. * SCATTERED SHOWERS WITH A SLIGHT CHANCE OF A THUNDERSTORM TOMORROW AFTERNOON. JEE/MTF //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS OVER THE REGION AND SLOWLY SHIFTING EAST. THE NEXT LOW PRESSURE SYSTEM IS OVER THE PLAINS AND GUIDANCE IS FINALLY ALIGNING WITH THE LOW PASSING THROUGH SOUTH CENTRAL IL LATE SATURDAY NIGHT THROUGH SUNDAY. FOR TODAY...THE WEAK FLOW WILL LEAD TO LIGHT WINDS VARYING FROM SOUTH TO SOUTHWEST WITH INCREASING CLOUDS THROUGH THIS EVENING. A LAKE BREEZE IS EXPECTED TO FORM...BUT FLOW IS STRONG ENOUGH ALOFT TO KEEP IT EAST OF THE TERMINALS. IN FACT CAN STILL CLEARLY SEE SMOKE FROM GARY MOVING NORTHEAST OVER THE LAKE SO NO LAKE BREEZE HAS FORMED YET. WINDS WEAKEN TONIGHT WITH SOUTH TO SOUTH- SOUTHWEST WINDS. WITH GUIDANCE AGREEING ON THE NEXT LOW...THINKING THE MAJORITY OF SHOWERS AND STORMS WILL REMAIN SOUTH OF THE TERMINALS. SCATTERED SHOWERS MAY MOVE OVER THE TERMINALS IN THE VERY LATE MORNING TO EARLY AFTERNOON. CONDITIONS DO NOT LOOK EXTREMELY FAVORABLE FOR THUNDERSTORMS AT THIS TIME...BUT WILL STILL MENTION A SLIGHT CHANCE OF THUNDER WITH HEAVY DOWNPOURS POSSIBLE. GUIDANCE HINTS AT MVFR CIGS AT GYY WITH A MUCH SMALLER CHANCE OVER THE EASTERN TERMINALS. WILL CONTINUE TO CARRY SCT025 AT RFD...BUT HAVE LOW CONFIDENCE IN MVFR CIGS. SSW TO SW WINDS MAINLY UNDER 10 KT ARE EXPECTED TOMORROW. JEE //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM THAT LAKE BREEZE WILL REMAIN EAST OF THE AREA LATE THIS AFTERNOON/EARLY THIS EVE. * MEDIUM IN COVERAGE AND TIMING OF SHOWERS TOMORROW...LOW CONFIDENCE IN THUNDERSTORMS. * HIGH IN ALL OTHER FORECAST ELEMENTS. JEE/MTF //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA. KREIN && .MARINE... 215 PM CDT LARGE AREA OF HIGH PRESSURE CENTERED JUST SOUTH OF LAKE MICHIGAN WILL SHIFT SOUTHEAST TONIGHT. A WEAK LOW PRESSURE SYSTEM IN SOUTH CENTRAL CANADA WILL DEEPEN SOME TONIGHT AS IT PASSES JUST NORTH OF THE UPPER GREAT LAKES REGION. THE PRESSURE GRADIENT INCREASES OVERNIGHT INTO EARLY SATURDAY MORNING...ESPECIALLY ALONG THE NORTHERN HALF OF THE LAKE. THIS WILL MAINTAIN SW FLOW TONIGHT...WITH WINDS APPROACHING 25-30 KT FOR A BRIEF TIME IN THE NORTH LATE TONIGHT. BEHIND THE LOW...HIGH PRESSURE BUILDS INTO SOUTHERN ONTARIO AND SENDS A COLD FRONT SOUTH DOWN THE LAKE SATURDAY AFTERNOON AND EVENING. ADDITIONALLY...AN AREA OF LOW PRESSURE IN THE CENTRAL PLAINS WILL SLOWLY DRIFT EAST TO THE OHIO VALLEY BY LATE SUNDAY THEN CONTINUE TO THE ATLANTIC SEABOARD MONDAY. THIS WILL HELP MAINTAIN OR A PERIOD OF NORTH TO NORTHEASTERLY WINDS. ADDITIONAL WEAKER LOW PRESSURE AREAS WILL PUSH TOWARD THE GREAT LAKES NEXT WEEK...MAINTAINING A SOUTH COMPONENT TO THE WIND WITH OCCASIONAL THUNDERSTORMS THROUGH MID 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 308 PM CDT Fri Aug 15 2014 .SHORT TERM...(This evening through Saturday) ISSUED AT 307 PM CDT FRI AUG 15 2014 Decaying MCS moving toward the CWA early this afternoon, with some light showers being reported near Galesburg. Most precipitation still west of the Mississippi River, with the HRRR showing it reaching about as far east as Springfield late this afternoon before diminishing. Latest LAPS soundings from Springfield and Jacksonville showing a fair amount of dry air below 700 mb, so am not expecting a lot of accumulation out of this. Shortwave currently moving southeast out of South Dakota/Nebraska starting to produce additional storms in Kansas, and this area of storms should expand as the wave moves eastward and the low level jet increases. HRRR and NAM show this next MCS approaching far western Illinois by late evening, but the other high-res models such as the ARW and NMM are a bit slower with arrival across the western CWA after about 2-3 am. All models show the MCS diminishing during the morning, but redevelopment taking place toward late afternoon in the west near a surface low in southeast Iowa. Extensive cloud cover should mitigate much of the severe weather potential, but precipitable water values increasing to over 2 inches will result in some locally heavy rains. && .LONG TERM...(Saturday night through Friday) ISSUED AT 307 PM CDT FRI AUG 15 2014 Occluded low pressure will reach western IL around 00z/7pm Saturday, bringing abundant moisture with the potential for some heavy rains. The latest model runs have shown a diminishing threat for strong storms in western IL, and SPC has reduced the 5% threat area to just west of a line from Rushville to Springfield. The threat for thunder in general will remain low due to limited ice formation and only weak instability. Limited afternoon sunshine after morning rain showers will also help to keep instability in check for Saturday evening. Rain will be likely during the evening southwest of Lincoln, then expand to the Indiana border after midnight Sat night. Likely rain will continue on Sunday east of I-55 as the slow moving low pressure system moves to near LWV by 00z/7pm Sunday. Bufkit sounding analysis shows better instability ahead of the low in our southeast areas Sunday afternoon, with MUCAPE up to 1500 J/kg, but confidence is low that storms will become very strong due to limited sunshine once again. Precipitable water values will remain very high through Sunday with 2" to 2.3" across most of central and southeast IL. Locally heavy rainfall from Saturday through Sunday evening could push 2 day totals between 2" and 3". As the low pulls east of IL on Sunday night, we expect diminishing precip chances from west to east, with a break in the rain expected at least on Monday. The Canadian GEM still indicated lingering rain in most of our area, so we left some slight chance PoPs for Monday. The next weather system will arrive quickly late Monday night and Tuesday, with increasing precip chances NW of the IL Monday night. Relatively good agreement of a warm front moving east across IL on Tuesday prompted chance PoPs across the board. The upper trough will deepen into IL on Tuesday night and Wed, with a trailing cold front lingering across IL through Thursday, keeping rain chances entrenched in the forecast through Thursday night. Warm and very muggy air will dominate the mid week period with the rain chances, as dewpoints remain in the low 70s and highs climb into the mid to upper 80s. Friday should bring a break in the rain as upper level ridging develops bringing even warmer air into central IL the following weekend. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 1235 PM CDT FRI AUG 15 2014 Area of decaying showers/storms dropping southeast from Iowa may brush KSPI/KPIA later this afternoon. A period of dry weather is then expected at these sites until after 06Z, when another convective complex moves east from Iowa/Missouri. At the TAF sites further east, have limited shower mention to about the 08-15Z time frame as VCSH, as several of the models weaken the overnight rain enough that the eastward extent is still in question. Have seen some cloud heights as low as around 3500 feet this afternoon with initial cumulus development, but most ceilings should be above 10KFT. Ceilings lower again late evening and overnight ahead of the convection, but have kept at VFR levels. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GEELHART LONG TERM...SHIMON AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
218 PM CDT FRI AUG 15 2014 .DISCUSSION... 331 AM CDT SHORT TERM...THROUGH FRIDAY NIGHT... FOR THE REMAINDER OF THE NIGHT...WITH THE CENTER OF HIGH PRESSURE MOVING OVERHEAD...WINDS HAVE BECOME LIGHT AND VARIABLE UNDER MOSTLY CLEAR SKIES. AN UNSEASONABLY...DRY AIRMASS IS IN PLACE WITH MANY LOCATIONS EXPECTED TO SEE MIN TEMPS DROP INTO THE MIDDLE TO UPPER 40S. WHILE THIS WILL LIKELY NOT REACH RECORD BREAKING LOW TEMPERATURES OVERNIGHT...THE LOWS WILL BE AROUND 15 DEGREES BELOW NORMAL. FRIDAY SHOULD REMAIN QUIET AS THE CENTER OF HIGH PRESSURE SETTLES INTO THE OHIO VALLEY AND A TROUGH OF LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. A SOUTHWESTERLY GRADIENT WILL SET UP WITH WINDS INCREASING FROM LIGHT AND VARIABLE TO ARND 10 KT THIS AFTERNOON. THE MAIN CONCERN FOR THIS AFTERNOON WILL BE WHETHER A LAKE BREEZE WILL FORM AND HOW FAR INLAND IT MIGHT PUSH...WHICH IN TURN WOULD AFFECT TEMPS ALONG THE LAKEFRONT. WITH MOSTLY CLEAR SKIES...TEMPERATURES SHOULD REACH ARND 80F THIS AFTERNOON. A WEAK GRADIENT AND ADEQUATE DIFFERENTIAL HEATING BETWEEN THE LAKE AND LAND SHOULD ALLOW FORMATION OF A LAKE BREEZE THIS AFTERNOON. HOWEVER...THE LATEST SHORT RANGE MODEL GUIDANCE SUGGESTS THAT WINDS THROUGH THE BOUNDARY LAYER SHOULD BE SWLY TO ARND 10KT. SO...WHILE THE DEVELOPMENT OF A LAKE BREEZE IS LIKELY...THE QUESTION BECOMES WHETHER IT WILL PENETRATE INLAND ENOUGH TO IMPACT TEMPERATURES ACROSS THE INLAND PORTIONS OF THE CHICAGO METRO AREA. AT THIS POINT...FEEL THAT THE LAKE BREEZE WILL REMAIN CLOSE TO SHORE...KEEPING LAKEFRONT MAX TEMPS IN THE MIDDLE 70S. THE NEXT FEATURE OF CONCERN WILL BE A NORTHERN STREAM SHORTWAVE CURRENTLY OVERTOPPING THE UPPER RIDGE OVER THE NRN PLAINS AND A MIDDLE STREAM SHORTWAVE OVER THE CENTRAL PLAINS. WITH WEAK UPPER LEVEL WINDS ON THE ERN SIDE OF THE UPPER RIDGE...THESE SYSTEMS WILL TRACK RATHER SLOWLY ACROSS THE PLAINS. THE LATEST GUIDANCE SUGGESTS THAT THE MORE SOUTHERN OF THE 2 SHORTWAVES WILL MOVE OUT AHEAD OF THE NRN STREAM SHORTWAVE...BRINGING INCREASING CLOUDINESS FRIDAY EVENING AND THEN STRENGTHENING AS IT MOVES OVER NRN MO/SRN IA BY SATURDAY MORNING. AN ASSOCIATED SFC LOW IS EXPECTED TO MOVE INTO SERN IA BY SATURDAY MORNING WITH A DEVELOPING WARM FRONT EXTENDING SEWD ALONG THE MISSISSIPPI RIVER. THE TRACK AND TIMING OF THE LEAD SHORTWAVE IS STILL A BIT UNCERTAIN WITH SOME TIMING AND INTENSITY DIFFERENCES AMONG THE SHORT RANGE GUIDANCE...THE GENERAL TREND SHOULD BE FOR INCREASING POPS OVER THE WRN PORTIONS OF THE CWA...WITH LOCATIONS ALONG AND POSSIBLE JUST EAST OF THE I-39 CORRIDOR SEE SOME RAIN AFTER MIDNIGHT FRIDAY NIGHT AND INTO THE EARLY MORNING HOURS. KREIN SATURDAY THROUGH SUNDAY... BIGGEST CONCERN WILL BE ON QPF TOTALS SAT INTO SUN WITH A SLOW MOVING WAVE. THIS COUPLED WITH INCREASED PWAT VALUES NEARING 2" PRIMARILY SAT...RAISES CONCERNS ABOUT SLOW MOVING STORMS THAT COULD BE EFFICIENT AT PRODUCING VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. THESE ANOMALOUSLY HIGH PWAT VALUES ARE PROGGED TO LINGER THRU SUN. 500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST AWAY FROM THE GREAT LAKES REGION...AS THE LONGWAVE PATTERN BEGINS TO TRANSITION INTO A QUASI-ZONAL SETUP. THIS WILL ALLOW SYSTEMS TO EASILY TRAVERSE THE CONUS FROM WEST TO EAST. HOWEVER THE WRINKLE WITH THIS SETUP WILL BE THAT OPER GUIDANCE IS INDICATING THE ACTIVE ZONE WILL SETUP ACROSS THE CWFA SAT AFTN THRU SUN EVE. GUIDANCE HAS BEEN CONSISTENT WITH DEVELOPING A SFC RIDGE OVER CENTRAL ONTARIO AND HELPING TO KEEP A STALLED FRONTAL BOUNDARY ACROSS THE MID-MISSOURI VALLEY STRETCHING EAST INTO THE OHIO VALLEY SAT NGT/SUN. AS PREVIOUSLY NOTED ABOUT A SLOW MOVING SYSTEM...GUIDANCE HAS A WAVE LIFTING NORTHEAST INTO THE SOUTHWEST PORTIONS OF THE CWFA SAT AFTN AND SLOWLY LIFTING NORTHEAST SUN. WITHIN THIS PERIOD IT IS BECOMING AN INCREASED CONCERN THAT IF CONVECTION DEVELOPS...WHICH APPEARS FAVORABLE...THAT SOME OF THESE STORMS COULD EASILY PUT DOWN HEAVY RAINFALL IN A SHORT PERIOD OF TIME. TEMPS SAT WILL LIKELY BE HELD DOWN SOMEWHAT GIVEN THE INCREASED SOLAR SHIELDING...HOWEVER WITH LLVL MOISTURE INCREASING DEW PTS WILL BE PUSHING INTO THE UPR 60S AND RESULT IN HUMID CONDS. WINDS WILL BE LIGHT AS WELL...GENERALLY FROM THE SOUTH. YET ANOTHER WEAK MID-LVL VORT WILL SLIDE EAST INTO THIS ZONE SUN AND WITH THE HIGH LLVL MOISTURE AND WEAK FLOW...THE CONCERN FOR LOCALLY HEAVY RAINFALL WILL PERSIST INTO SUN EVE. FORTUNATELY GUIDANCE HAS BEEN INDICATING THAT THE QUASI-STATIONARY FRONTAL BOUNDARY MAY SLIP FURTHER SOUTH AND COULD DISPLACE THE LOCATION OF HEAVIER RAINFALL TO THE SOUTHERN CWFA SUN AFTN/EVE. THIS WOULD ALLOW A SLIGHTLY DRIER NORTHERLY WIND TO PROVIDE SOME RELIEF TO AREAS NORTH OF I-80 WITH HIGHS IN THE UPR 70S SUN. MONDAY THROUGH THURSDAY... ENSEMBLES ARE DEMONSTRATING SOME SPREAD IN THE MEDIUM TERM THRU TUE...WITH REGARDS TO THE TIMING OF THE FLOW TRANSITIONING OUT OF THE QUASI-ZONAL SETUP. BEYOND MID-WEEK GUIDANCE IS RATHER CONSISTENT IN REDEVELOPING A NORTH ATLANTIC RIDGE...ALONG WITH SOME RIDGING TRYING TO DEVELOP ACROSS THE PAC-NW. WHILE CONFIDENCE IS LOW...THIS COULD SUGGEST THAT SOME DEGREE OF TROUGHING COULD RETURN TO THE CENTRAL CONUS AND PERHAPS BRING SOME QUIETER WEATHER BACK TO THE CWFA. HOWEVER...CONFIDENCE IS LOW AS THERE IS STILL SOME SPREAD AMONGST MEMBERS. OPER GUIDANCE IS ALSO SHOWING CONSIDERABLE SPREAD IN THE EXTENDED PERIODS. THE OVERALL THEME APPEARS TO BE TEMPS RETURNING TO SEASONAL CONDS IN THE LOW TO PSBLY MID 80S WITH OVERNIGHT LOWS IN THE 60S. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SCATTERED SHOWERS WITH A SLIGHT CHANCE OF A THUNDERSTORM TOMORROW AFTERNOON. JEE //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS OVER THE REGION AND SLOWLY SHIFTING EAST. THE NEXT LOW PRESSURE SYSTEM IS OVER THE PLAINS AND GUIDANCE IS FINALLY ALIGNING WITH THE LOW PASSING THROUGH SOUTH CENTRAL IL LATE SATURDAY NIGHT THROUGH SUNDAY. FOR TODAY...THE WEAK FLOW WILL LEAD TO LIGHT WINDS VARYING FROM SOUTH TO SOUTHWEST WITH INCREASING CLOUDS THROUGH THIS EVENING. A LAKE BREEZE IS EXPECTED TO FORM...BUT FLOW IS STRONG ENOUGH ALOFT TO KEEP IT EAST OF THE TERMINALS. IN FACT CAN STILL CLEARLY SEE SMOKE FROM GARY MOVING NORTHEAST OVER THE LAKE SO NO LAKE BREEZE HAS FORMED YET. WINDS WEAKEN TONIGHT WITH SOUTH TO SOUTH- SOUTHWEST WINDS. WITH GUIDANCE AGREEING ON THE NEXT LOW...THINKING THE MAJORITY OF SHOWERS AND STORMS WILL REMAIN SOUTH OF THE TERMINALS. SCATTERED SHOWERS MAY MOVE OVER THE TERMINALS IN THE VERY LATE MORNING TO EARLY AFTERNOON. CONDITIONS DO NOT LOOK EXTREMELY FAVORABLE FOR THUNDERSTORMS AT THIS TIME...BUT WILL STILL MENTION A SLIGHT CHANCE OF THUNDER WITH HEAVY DOWNPOURS POSSIBLE. GUIDANCE HINTS AT MVFR CIGS AT GYY WITH A MUCH SMALLER CHANCE OVER THE EASTERN TERMINALS. WILL CONTINUE TO CARRY SCT025 AT RFD...BUT HAVE LOW CONFIDENCE IN MVFR CIGS. SSW TO SW WINDS MAINLY UNDER 10 KT ARE EXPECTED TOMORROW. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE THE LAKE BREEZE REMAINING EAST OF THE TERMINALS. * MEDIUM CONFIDENCE IN COVERAGE AND TIMING OF SHOWERS TOMORROW...LOW CONFIDENCE IN THUNDERSTORMS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA. KREIN && .MARINE... 215 PM CDT LARGE AREA OF HIGH PRESSURE CENTERED JUST SOUTH OF LAKE MICHIGAN WILL SHIFT SOUTHEAST TONIGHT. A WEAK LOW PRESSURE SYSTEM IN SOUTH CENTRAL CANADA WILL DEEPEN SOME TONIGHT AS IT PASSES JUST NORTH OF THE UPPER GREAT LAKES REGION. THE PRESSURE GRADIENT INCREASES OVERNIGHT INTO EARLY SATURDAY MORNING...ESPECIALLY ALONG THE NORTHERN HALF OF THE LAKE. THIS WILL MAINTAIN SW FLOW TONIGHT...WITH WINDS APPROACHING 25-30 KT FOR A BRIEF TIME IN THE NORTH LATE TONIGHT. BEHIND THE LOW...HIGH PRESSURE BUILDS INTO SOUTHERN ONTARIO AND SENDS A COLD FRONT SOUTH DOWN THE LAKE SATURDAY AFTERNOON AND EVENING. ADDITIONALLY...AN AREA OF LOW PRESSURE IN THE CENTRAL PLAINS WILL SLOWLY DRIFT EAST TO THE OHIO VALLEY BY LATE SUNDAY THEN CONTINUE TO THE ATLANTIC SEABOARD MONDAY. THIS WILL HELP MAINTAIN OR A PERIOD OF NORTH TO NORTHEASTERLY WINDS. ADDITIONAL WEAKER LOW PRESSURE AREAS WILL PUSH TOWARD THE GREAT LAKES NEXT WEEK...MAINTAINING A SOUTH COMPONENT TO THE WIND WITH OCCASIONAL THUNDERSTORMS THROUGH MID 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 132 PM CDT Fri Aug 15 2014 .UPDATE... ISSUED AT 129 PM CDT FRI AUG 15 2014 Have sent out an update to lower high temperatures across primarily the northwest half of the CWA today. Extensive cloud cover from decaying MCS has limited the temperature rise into the lower 70s as of early afternoon. With more clouds and some showers moving in later this afternoon, temperatures likely to rise only a couple more degrees. UPDATE ISSUED AT 1009 AM CDT FRI AUG 15 2014 Area of showers and thunderstorms advancing east across Iowa and northern Missouri this morning, ahead of a shortwave across the Plains. Latest high-resolution models show this progressing toward the Mississippi River the remainder of the morning, before decaying in west central Illinois, but the HRRR suggests some light showers may make it as far east as Springfield by 4 pm. Existing 20% PoP`s across the western CWA still sufficient. Temperatures off to a chilly start in the northeast CWA underneath an area of high pressure, with 44 degrees observed at the Danville airport for a low. A decent recovery so far as sunshine as boosted temperatures into the lower 60s. Remainder of the CWA is largely in the upper 60s/lower 70s at 10 am with clouds increasing. Question will be how much the clouds impact the temperatures this afternoon, especially across the west. Have only made minor changes for now, generally around a degree or so, to blend in with the current trends. Latest HRRR and RAP seem a bit too high with mid 80s this afternoon despite the cloud cover, so have leaned more toward the LAMP guidance. && .SHORT TERM...(Today and tonight) ISSUED AT 328 AM CDT FRI AUG 15 2014 Boundary that pushed across parts of central thru southeast Illinois yesterday has finally shifted just south of Interstate 70 early this morning. Rather tight temp/dew point gradient across the forecast area with upper 40 dew points across the northeast, while over our far southwest counties, readings were in the low to mid 60s. Quite a bit of mid and high level cloudiness was streaming southeast into Iowa and extreme west central Illinois ahead of our next shortwave over western Nebraska, and that cloud cover will have an affect on afternoon highs, especially across the north and west. High pressure just to our north and east will drift slowly away from our area today with a return southerly flow developing by this afternoon and evening. Forecast soundings continue to indicate quite a bit of dry air in the low levels of the atmosphere thru this evening so will keep our area dry but will have to keep an eye out for our western counties as some of the shower activity forecast over Iowa today may approach our far west by late afternoon or early this evening. For now, will keep any mention of rain out in the west until early this evening. Models continue to indicate the more favorable 850 mb theta-e advection/moisture convergence and low level jet position for overnight convection would be to our west with whatever develops over Iowa late tonight pushing into our far western areas after midnight. PoPs will be on the increase, especially across the west this evening with rain probably holding off over areas east of I-57 until Saturday morning. && .LONG TERM...(Saturday through Friday) ISSUED AT 328 AM CDT FRI AUG 15 2014 An unsettled weather pattern taking shape over central and southeast IL with daily chances of showers and thunderstorms from this weekend through the middle of next week, as humid conditions return along with building heat by the middle of next week. 00Z forecast models continue to show short waves/upper level low/trof moving into IL later this weekend though still some timing differences and qpf amounts vary between models and from run to run. Still looks like increase chances of showers and thunderstorms from west to east during the weekend with highest chances SW counties Sat and shifting into eastern IL by Sunday night. SPC has 5% risk of severe storms along and west of a Springfield to Peoria line Saturday while slight risk of severe storms (15%) is WSW of IL over central and northern MO. SPC then has 5% risk of severe storms Sunday SE of a Champaign to Shelbyville line mainly in the afternoon and early evening hours. Heavy rain threat also this weekend especially Sunday with precipitable water values peaking from 2-2.50 inches. Highs 80-85F over central IL this weekend with mid 80s over southeast IL. Humid this weekend with dew points in the upper 60s and lower 70s. Short wave trof/low exits east of IL early next work week but more energy arriving thereafter to keep chances of showers and thunderstorms going into middle of next week as humid dew points in the upper 60s to mid 70s prevail. Temperatures to also heat up into the mid to upper 80s by middle and later part of next week as upper level heights rise over IL. SW parts of CWA approaching 90F from Wed-Fri and afternoon heat indices in the mid to upper 90s. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 1235 PM CDT FRI AUG 15 2014 Area of decaying showers/storms dropping southeast from Iowa may brush KSPI/KPIA later this afternoon. A period of dry weather is then expected at these sites until after 06Z, when another convective complex moves east from Iowa/Missouri. At the TAF sites further east, have limited shower mention to about the 08-15Z time frame as VCSH, as several of the models weaken the overnight rain enough that the eastward extent is still in question. Have seen some cloud heights as low as around 3500 feet this afternoon with initial cumulus development, but most ceilings should be above 10KFT. Ceilings lower again late evening and overnight ahead of the convection, but have kept at VFR levels. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...SMITH LONG TERM...07 AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1102 AM CDT FRI AUG 15 2014 .DISCUSSION... 331 AM CDT SHORT TERM...THROUGH FRIDAY NIGHT... FOR THE REMAINDER OF THE NIGHT...WITH THE CENTER OF HIGH PRESSURE MOVING OVERHEAD...WINDS HAVE BECOME LIGHT AND VARIABLE UNDER MOSTLY CLEAR SKIES. AN UNSEASONABLY...DRY AIRMASS IS IN PLACE WITH MANY LOCATIONS EXPECTED TO SEE MIN TEMPS DROP INTO THE MIDDLE TO UPPER 40S. WHILE THIS WILL LIKELY NOT REACH RECORD BREAKING LOW TEMPERATURES OVERNIGHT...THE LOWS WILL BE AROUND 15 DEGREES BELOW NORMAL. FRIDAY SHOULD REMAIN QUIET AS THE CENTER OF HIGH PRESSURE SETTLES INTO THE OHIO VALLEY AND A TROUGH OF LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. A SOUTHWESTERLY GRADIENT WILL SET UP WITH WINDS INCREASING FROM LIGHT AND VARIABLE TO ARND 10 KT THIS AFTERNOON. THE MAIN CONCERN FOR THIS AFTERNOON WILL BE WHETHER A LAKE BREEZE WILL FORM AND HOW FAR INLAND IT MIGHT PUSH...WHICH IN TURN WOULD AFFECT TEMPS ALONG THE LAKEFRONT. WITH MOSTLY CLEAR SKIES...TEMPERATURES SHOULD REACH ARND 80F THIS AFTERNOON. A WEAK GRADIENT AND ADEQUATE DIFFERENTIAL HEATING BETWEEN THE LAKE AND LAND SHOULD ALLOW FORMATION OF A LAKE BREEZE THIS AFTERNOON. HOWEVER...THE LATEST SHORT RANGE MODEL GUIDANCE SUGGESTS THAT WINDS THROUGH THE BOUNDARY LAYER SHOULD BE SWLY TO ARND 10KT. SO...WHILE THE DEVELOPMENT OF A LAKE BREEZE IS LIKELY...THE QUESTION BECOMES WHETHER IT WILL PENETRATE INLAND ENOUGH TO IMPACT TEMPERATURES ACROSS THE INLAND PORTIONS OF THE CHICAGO METRO AREA. AT THIS POINT...FEEL THAT THE LAKE BREEZE WILL REMAIN CLOSE TO SHORE...KEEPING LAKEFRONT MAX TEMPS IN THE MIDDLE 70S. THE NEXT FEATURE OF CONCERN WILL BE A NORTHERN STREAM SHORTWAVE CURRENTLY OVERTOPPING THE UPPER RIDGE OVER THE NRN PLAINS AND A MIDDLE STREAM SHORTWAVE OVER THE CENTRAL PLAINS. WITH WEAK UPPER LEVEL WINDS ON THE ERN SIDE OF THE UPPER RIDGE...THESE SYSTEMS WILL TRACK RATHER SLOWLY ACROSS THE PLAINS. THE LATEST GUIDANCE SUGGESTS THAT THE MORE SOUTHERN OF THE 2 SHORTWAVES WILL MOVE OUT AHEAD OF THE NRN STREAM SHORTWAVE...BRINGING INCREASING CLOUDINESS FRIDAY EVENING AND THEN STRENGTHENING AS IT MOVES OVER NRN MO/SRN IA BY SATURDAY MORNING. AN ASSOCIATED SFC LOW IS EXPECTED TO MOVE INTO SERN IA BY SATURDAY MORNING WITH A DEVELOPING WARM FRONT EXTENDING SEWD ALONG THE MISSISSIPPI RIVER. THE TRACK AND TIMING OF THE LEAD SHORTWAVE IS STILL A BIT UNCERTAIN WITH SOME TIMING AND INTENSITY DIFFERENCES AMONG THE SHORT RANGE GUIDANCE...THE GENERAL TREND SHOULD BE FOR INCREASING POPS OVER THE WRN PORTIONS OF THE CWA...WITH LOCATIONS ALONG AND POSSIBLE JUST EAST OF THE I-39 CORRIDOR SEE SOME RAIN AFTER MIDNIGHT FRIDAY NIGHT AND INTO THE EARLY MORNING HOURS. KREIN SATURDAY THROUGH SUNDAY... BIGGEST CONCERN WILL BE ON QPF TOTALS SAT INTO SUN WITH A SLOW MOVING WAVE. THIS COUPLED WITH INCREASED PWAT VALUES NEARING 2" PRIMARILY SAT...RAISES CONCERNS ABOUT SLOW MOVING STORMS THAT COULD BE EFFICIENT AT PRODUCING VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. THESE ANOMALOUSLY HIGH PWAT VALUES ARE PROGGED TO LINGER THRU SUN. 500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST AWAY FROM THE GREAT LAKES REGION...AS THE LONGWAVE PATTERN BEGINS TO TRANSITION INTO A QUASI-ZONAL SETUP. THIS WILL ALLOW SYSTEMS TO EASILY TRAVERSE THE CONUS FROM WEST TO EAST. HOWEVER THE WRINKLE WITH THIS SETUP WILL BE THAT OPER GUIDANCE IS INDICATING THE ACTIVE ZONE WILL SETUP ACROSS THE CWFA SAT AFTN THRU SUN EVE. GUIDANCE HAS BEEN CONSISTENT WITH DEVELOPING A SFC RIDGE OVER CENTRAL ONTARIO AND HELPING TO KEEP A STALLED FRONTAL BOUNDARY ACROSS THE MID-MISSOURI VALLEY STRETCHING EAST INTO THE OHIO VALLEY SAT NGT/SUN. AS PREVIOUSLY NOTED ABOUT A SLOW MOVING SYSTEM...GUIDANCE HAS A WAVE LIFTING NORTHEAST INTO THE SOUTHWEST PORTIONS OF THE CWFA SAT AFTN AND SLOWLY LIFTING NORTHEAST SUN. WITHIN THIS PERIOD IT IS BECOMING AN INCREASED CONCERN THAT IF CONVECTION DEVELOPS...WHICH APPEARS FAVORABLE...THAT SOME OF THESE STORMS COULD EASILY PUT DOWN HEAVY RAINFALL IN A SHORT PERIOD OF TIME. TEMPS SAT WILL LIKELY BE HELD DOWN SOMEWHAT GIVEN THE INCREASED SOLAR SHIELDING...HOWEVER WITH LLVL MOISTURE INCREASING DEW PTS WILL BE PUSHING INTO THE UPR 60S AND RESULT IN HUMID CONDS. WINDS WILL BE LIGHT AS WELL...GENERALLY FROM THE SOUTH. YET ANOTHER WEAK MID-LVL VORT WILL SLIDE EAST INTO THIS ZONE SUN AND WITH THE HIGH LLVL MOISTURE AND WEAK FLOW...THE CONCERN FOR LOCALLY HEAVY RAINFALL WILL PERSIST INTO SUN EVE. FORTUNATELY GUIDANCE HAS BEEN INDICATING THAT THE QUASI-STATIONARY FRONTAL BOUNDARY MAY SLIP FURTHER SOUTH AND COULD DISPLACE THE LOCATION OF HEAVIER RAINFALL TO THE SOUTHERN CWFA SUN AFTN/EVE. THIS WOULD ALLOW A SLIGHTLY DRIER NORTHERLY WIND TO PROVIDE SOME RELIEF TO AREAS NORTH OF I-80 WITH HIGHS IN THE UPR 70S SUN. MONDAY THROUGH THURSDAY... ENSEMBLES ARE DEMONSTRATING SOME SPREAD IN THE MEDIUM TERM THRU TUE...WITH REGARDS TO THE TIMING OF THE FLOW TRANSITIONING OUT OF THE QUASI-ZONAL SETUP. BEYOND MID-WEEK GUIDANCE IS RATHER CONSISTENT IN REDEVELOPING A NORTH ATLANTIC RIDGE...ALONG WITH SOME RIDGING TRYING TO DEVELOP ACROSS THE PAC-NW. WHILE CONFIDENCE IS LOW...THIS COULD SUGGEST THAT SOME DEGREE OF TROUGHING COULD RETURN TO THE CENTRAL CONUS AND PERHAPS BRING SOME QUIETER WEATHER BACK TO THE CWFA. HOWEVER...CONFIDENCE IS LOW AS THERE IS STILL SOME SPREAD AMONGST MEMBERS. OPER GUIDANCE IS ALSO SHOWING CONSIDERABLE SPREAD IN THE EXTENDED PERIODS. THE OVERALL THEME APPEARS TO BE TEMPS RETURNING TO SEASONAL CONDS IN THE LOW TO PSBLY MID 80S WITH OVERNIGHT LOWS IN THE 60S. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LAKE BREEZE SHOULD REMAIN EAST OF THE TERMINALS...SO EXPECTING SW WINDS LESS THAN 10 KT. JEE //DISCUSSION...UPDATED 12Z... HIGH PRESSURE WILL SETTLE INTO THE OHIO VALLEY TODAY AS A TROUGH OF LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. A MORE SWLY GRADIENT WILL DEVELOP THROUGH THE DAY. THE WEAK GRADIENT AND DIFFERENTIAL HEATING UNDER SCT SKY COVER SHOULD ALLOW FOR LAKE BREEZE DEVELOPMENT AGAIN TODAY...BUT WINDS JUST OFF THE DECK SHOULD APPROACH 10KT AND...AT THIS TIME...DO NOT ANTICIPATE THAT THE LAKE BREEZE WILL PENETRATE INLAND FAR ENOUGH TO IMPACT ORD/MDW...THOUGH IT COULD BE CLOSE FOR MDW AND THAT SITE COULD TURN ELY. THE LAKE BREEZE SHOULD PUSH INLAND OF GYY...WHICH SHOULD TURN ENELY IN THE AFTERNOON. RFD/DPA SHOULD REMAIN WELL WITHING THE SYNOPTIC FLOW OF SWLY...VEERING WNWLY IN THE AFTERNOON. A MID LEVEL IMPULSE APPROACHING THE MIDDLE MISSISSIPPI VALLEY LATE TONIGHT WILL BRING INCREASING CLOUD COVER AND THE NEXT ROUND OF PCPN TO THE REGION. ANTICIPATE THAT PCPN SHOULD REACH RFD SHORTLY BY DAYBREAK AND REACH THE CHICAGO AREA TERMINALS BY LATE MORNING. THERE SHOULD BE SOME TS WITH THIS SYSTEM...BUT THE CHANCES WILL BE GREATER AFTER 18Z THAN BEFORE. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH CONFIDENCE IN WIND TRENDS AND LAKE BREEZE NOT REACHING ORD/MDW. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA. KREIN && .MARINE... 350 AM CDT SURFACE HIGH PRESSURE IS NOW CENTERED JUST SOUTH OF THE SOUTHERN TIP OF LAKE MICHIGAN WILL CONTINUE TO BUILD SOUTHEAST INTO THE OHIO VALLEY FRIDAY. WITH SFC TROUGHING OVER THE CNTRL PLAINS WINDS WILL MORE SOUTHWESTERLY FOR FRIDAY AND INTO SATURDAY. A COLD FRONT IS EXPECTED TO DROP SOUTH DOWN THE LENGTH OF LAKE MICHIGAN...THROUGH THE NORTHERN HALF OF THE LAKE SATURDAY AFTERNOON AND AND REACHING THE SOUTHERN END OF THE LAKE LATE SATURDAY NIGHT. WINDS SHOULD SHIFT TO NORTHERLY FOLLOWING THE FROPA WITH A SHORT PERIOD WITH WINDS UP 20 KT. AS HIGH PRESSURE BUILDS ACROSS ONTARIO SATURDAY NIGHT WHILE LOW PRESSURE MOVES THROUGH IL/IN...WINDS SHOULD BECOME ELY ACROSS THE LAKE. THE PROGRESSION OF THE PATTERN SHOULD BE RELATIVELY SLOW...WITH GENERALLY ELY WINDS OVER THE LAKE INTO EARLY NEXT WEEK. KREIN && .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 1020 AM CDT Fri Aug 15 2014 .UPDATE... ISSUED AT 1009 AM CDT FRI AUG 15 2014 Area of showers and thunderstorms advancing east across Iowa and northern Missouri this morning, ahead of a shortwave across the Plains. Latest high-resolution models show this progressing toward the Mississippi River the remainder of the morning, before decaying in west central Illinois, but the HRRR suggests some light showers may make it as far east as Springfield by 4 pm. Existing 20% PoP`s across the western CWA still sufficient. Temperatures off to a chilly start in the northeast CWA underneath an area of high pressure, with 44 degrees observed at the Danville airport for a low. A decent recovery so far as sunshine as boosted temperatures into the lower 60s. Remainder of the CWA is largely in the upper 60s/lower 70s at 10 am with clouds increasing. Question will be how much the clouds impact the temperatures this afternoon, especially across the west. Have only made minor changes for now, generally around a degree or so, to blend in with the current trends. Latest HRRR and RAP seem a bit too high with mid 80s this afternoon despite the cloud cover, so have leaned more toward the LAMP guidance. && .SHORT TERM...(Today and tonight) ISSUED AT 328 AM CDT FRI AUG 15 2014 Boundary that pushed across parts of central thru southeast Illinois yesterday has finally shifted just south of Interstate 70 early this morning. Rather tight temp/dew point gradient across the forecast area with upper 40 dew points across the northeast, while over our far southwest counties, readings were in the low to mid 60s. Quite a bit of mid and high level cloudiness was streaming southeast into Iowa and extreme west central Illinois ahead of our next shortwave over western Nebraska, and that cloud cover will have an affect on afternoon highs, especially across the north and west. High pressure just to our north and east will drift slowly away from our area today with a return southerly flow developing by this afternoon and evening. Forecast soundings continue to indicate quite a bit of dry air in the low levels of the atmosphere thru this evening so will keep our area dry but will have to keep an eye out for our western counties as some of the shower activity forecast over Iowa today may approach our far west by late afternoon or early this evening. For now, will keep any mention of rain out in the west until early this evening. Models continue to indicate the more favorable 850 mb theta-e advection/moisture convergence and low level jet position for overnight convection would be to our west with whatever develops over Iowa late tonight pushing into our far western areas after midnight. PoPs will be on the increase, especially across the west this evening with rain probably holding off over areas east of I-57 until Saturday morning. && .LONG TERM...(Saturday through Friday) ISSUED AT 328 AM CDT FRI AUG 15 2014 An unsettled weather pattern taking shape over central and southeast IL with daily chances of showers and thunderstorms from this weekend through the middle of next week, as humid conditions return along with building heat by the middle of next week. 00Z forecast models continue to show short waves/upper level low/trof moving into IL later this weekend though still some timing differences and qpf amounts vary between models and from run to run. Still looks like increase chances of showers and thunderstorms from west to east during the weekend with highest chances SW counties Sat and shifting into eastern IL by Sunday night. SPC has 5% risk of severe storms along and west of a Springfield to Peoria line Saturday while slight risk of severe storms (15%) is WSW of IL over central and northern MO. SPC then has 5% risk of severe storms Sunday SE of a Champaign to Shelbyville line mainly in the afternoon and early evening hours. Heavy rain threat also this weekend especially Sunday with precipitable water values peaking from 2-2.50 inches. Highs 80-85F over central IL this weekend with mid 80s over southeast IL. Humid this weekend with dew points in the upper 60s and lower 70s. Short wave trof/low exits east of IL early next work week but more energy arriving thereafter to keep chances of showers and thunderstorms going into middle of next week as humid dew points in the upper 60s to mid 70s prevail. Temperatures to also heat up into the mid to upper 80s by middle and later part of next week as upper level heights rise over IL. SW parts of CWA approaching 90F from Wed-Fri and afternoon heat indices in the mid to upper 90s. && .AVIATION...(For the 12Z TAFS through 12Z Saturday morning) ISSUED AT 615 AM CDT FRI AUG 15 2014 VFR conditions are expected thru this evening with the threat for cigs and vsbys to lower to MVFR towards 12z, especially in PIA and SPI as rain chances increase. A band of lower VFR cigs has developed over the past several hours from near PIA southeast towards DEC with cigs ranging from SCT-BKN at 3500-4500 feet. Forecast soundings indicate these should become more scattered later this morning, with mainly a mid and high level deck expected into the afternoon hours. As a weather system over the central Plains this morning moves in our direction later today and tonight, rain chances will start to increase, especially across the west tonight with the potential for cigs to lower to MVFR at PIA and SPI with scattered TSRA possible after 05z. Surface winds will not be much of a factor thru tonight with winds out of the east and southeast at 4 to 9 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...SMITH LONG TERM...07 AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1122 AM CDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1120 AM CDT FRI AUG 15 2014 LOW LEVEL JET WAS BEGINNING TO WEAKEN AND SO WAS THE MCS IN CENTRAL IA. THE ACTIVITY WAS MOVING SOUTHEAST IN THE NORTHWEST FLOW ALOFT. THE HRRR MESO MODEL PUSHES SCATTERED SHOWERS INTO OUR WESTERN AND SOUTHERN CWA THROUGH EARLY THIS AFTERNOON THEN WEAKENING. THERE MAY ALSO BE ISOLATED THUNDERSTORMS. IN OUR NORTHEAST CWA DRIER AIR IN PLACE AND MORE SUNSHINE EXPECTED THERE. OTHERWISE THICKER CLOUD COVER IN OUR SOUTHWEST WILL KEEP TEMPERATURES IN THE MID 70S. HAVE UPDATED THE GRIDS TO LOWER TEMPERATURES AND INCREASE SKY COVER. WILL MONITOR TRENDS AND MAY HAVE TO LOWER READINGS EVEN MORE. && .SYNOPSIS... ISSUED AT 233 AM CDT FRI AUG 15 2014 NORTHWEST FLOW ALOFT ACROSS THE MIDWEST IS PUSHING CONVECTIVE ACTIVITY OVER SD-MN AREA INTO IOWA...WHILE THE KEY SYSTEM OF THE DAY...AN UPPER LEVEL SHORTWAVE TROUGH AND AREA OF PRECIP...IS STILL EVOLVING OVER NE AND KS. SURFACE HIGH PRESSURE IS TO THE EAST WHILE A WARMER AND MORE MOIST AIR MASS RESIDES TO OUR WEST AS ILLUSTRATED BY A 20 DEGREE DEW POINT GRADIENT FROM CHICAGO TO DES MOINES. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 233 AM CDT FRI AUG 15 2014 CURRENT ONGOING SHOWER AND THUNDERSTORM ACTIVITY IS MAINLY NUISANCE STUFF BEFORE THE MORE SIGNIFICANT ACTIVITY LATER TONIGHT. AIR MASS OVER MOST OF THE CWA IS CURRENTLY RATHER COOL AND DRY...AND THIS WILL CHALLENGE THE PERSISTENCE OF THE CONVECTIVE ACTIVITY AS IT MOVES SOUTHEASTWARD THROUGH THE MORNING. SHORT RANGE MODEL TRENDS SUGGEST THESE STORMS WILL WEAKEN AS THEY MOVE INTO OUR AREA...THUS HAVE ONLY LOW POPS. AS THE DAY PROGRESSES THE AIR MASS OVER THE AREA WILL BECOME MORE HUMID WITH PWS CURRENTLY AROUND .75 INCH INCREASING UP TO AROUND 1.25 INCH BY 00Z. THIS IS AHEAD OF THE TROUGH WHICH IS FORECAST TO MOVE SLOWLY EAST TODAY AND TONIGHT AND FOCUS THUNDERSTORM ACTIVITY DURING THE OVERNIGHT HOURS...PRIMARILY IN THE SOUTHWEST PART OF THE CWA. STORMS OVERNIGHT WILL ALSO BE SUPPORTED BY THE LLJ AND 850 MB BOUNDARY...THOUGH MODELS VARY ON THE DETAILS. FOLLOWED A SOLUTION SUGGESTED BY THE 00Z ECMWF AND GEM PLUS A SPEEDIER NAM. WITH THE MOISTENING AIR MASS...LOCALLY HEAVY RAIN IS POSSIBLE BUT THE THREAT OF ANYTHING MORE THAN ISOLATED SEVERE WEATHER IS LOW DUE TO LIMITED INSTABILITY. WARM ADVECTION TODAY WILL BE COUNTERED BY MORE EXTENSIVE CLOUDINESS THAN WE EXPERIENCED YESTERDAY...THUS EXPECT LITTLE NET CHANGE IN MAX TEMPS AS THOSE FACTORS BALANCE OUT. WARMER AIR AND CLOUDS TONIGHT HOWEVER WILL KEEP MIN TEMPS SEVERAL DEGREES WARMER THAN THIS MORNINGS LOWS. WOLF .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 233 AM CDT FRI AUG 15 2014 DAILY CHANCES OF SHOWERS AND THUNDERSTORMS WILL TYPICAL MID AUGUST TEMPERATURES. OVERVIEW...INITIALIZATION AND VERIFICATION GOOD WITH MINOR BL MOISTURE AND PRECIPITATION BIASES WITH AMERICAN SOLUTIONS A BIT TOO MOIST AND TOO COVERAGE OF QPF AMOUNTS. RUN TO RUN VARIANCE SUPPORTS A 75/25 MIX OF THE HI-RES ECMWF TO A MIX OF GEM-NH/GFS. LARGE SCALE FORCING TOOLS SUGGEST LITTLE OR NO SEVERE RISK WITH SEVERAL EPISODES OF SHOWERS AND STORMS OF MOSTLY THE PULSE VARIETY WITH SOME AREAS OF PRECIPITATION...MAINLY SATURDAY. LONG TERM FORECAST CONFIDENCE...AVERAGE (GOOD)...TIMING OF SHOWERS AND STORMS AND LOCATION COVERAGE POOR TO FAIR...EXCEPT HIGHER CONFIDENCE IN SATURDAY/S EVENT. INITIALIZATION AND VERIFICATION COUPLED WITH SERIES OF UPPER DISTURBANCE MAKE FOR MARGINAL CONFIDENCE OF POPS WITH AGAIN THE BEST CONFIDENCE SATURDAY/S EVENT IN SOUTHERN PORTIONS. TEMPERATURES SHOULD GENERALLY BE WITHIN 3 DEGREES OF FORECAST. SATURDAY...A MCS EVENT SUGGESTED TO AFFECT THE REGION WITH LIKELY POPS SOUTH AND MODERATE TO HIGH CHANCE POPS NORTH. PW VALUES AOA 1.5" SUGGESTING MODERATE TO LOCALLY SOME LOWER END RAIN AMOUNTS TO 1 INCH...OR MORE. BEST FORCING SUGGESTED TO BE ALONG AND SOUTH OF HIGHWAY 34 WITH EVAPORATIVE COOLING THAT SHOULD KEEP SOME AREAS HIGHS IN THE UPPER 70S....OTHERWISE...LOWER 80S. SATURDAY NIGHT...LINGERING SHOWERS AND EMBEDDED THUNDER ALONG WEAK BOUNDARY IN NW FLOW WITH CHANCE POPS SUPPORTED...MINS WITH CLOUDS IN THE MID TO UPPER 60S. SUNDAY THROUGH THURSDAY...NW FLOW CONTINUES WITH A SERIES OF WEAK DISTURBANCES SUGGESTING ISOLATED TO CHANCE POPS EVERY FORECAST PERIOD ATTM. MINOR CHANGES IN TEMPERATURES WITH SLIGHTLY WARMER TEMPERATURES LATE NEXT WEEK. HIGHS MOSTLY IN THE LOWER 80S...RISING INTO THE MID/UPPER 80S BY THURSDAY. LOWS IN THE MID/UPPER 60S. LIMITED INSTABILITY...SHEAR AND FORCING SUGGEST LITTLE OR NO ORGANIZED SEVERE RISK ATTM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1120 AM CDT FRI AUG 15 2014 VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH THE PERIOD. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON WILL BE WEAK AND LIKELY HAVE LITTLE IF ANY IMPACT ON AREA TAF SITES. AS WARMER AND MORE HUMID AIR PUSHES INTO THE AREA TONIGHT AS A SHORT WAVE TROUGH PROGRESSES INTO THE MIDWEST...A GREATER CHANCE OF THUNDERSTORMS IS EXPECTED OVERNIGHT TOWARD MORNING...ESPECIALLY IN THE BRL AREA. THESE STORMS WILL LIKELY PRODUCE MVFR OR IFR CONDITIONS... THOUGH CHANCES ARE LOWER THAT THEY WILL OCCUR AT CID...MLI AND DBQ COMPARED TO BRL. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...HAASE SYNOPSIS...WOLF SHORT TERM...WOLF LONG TERM...NICHOLS AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
529 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 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 526 PM MDT SAT AUG 16 2014 ISOLATED THUNDERSTORMS SHOULD DISSIPATE AFTER SUNSET. OTHERWISE VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK OVERNIGHT AND SUNDAY MORNING. MORE STORMS WILL BE IN THE VICINITY OF BOTH SITES SUNDAY AFTERNOON. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...RRH AVIATION...FS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
142 PM CDT Fri Aug 15 2014 ...UPDATED AVIATION... .SHORT TERM...(Today and tonight) ISSUED AT 347 AM CDT FRI AUG 15 2014 A weak shortwave trough was approaching western Kansas this morning. Ahead of this feature, elevated convection was ongoing near the interstate 70 corridor. This upper level feature will pass across southwest Kansas today. A narrow ribbon of low level moisture from El Paso into eastern Mew Mexico is expected to advect north-northeastward into southwest Kansas, leading to destabilization. Surface based CAPE values will approach 1500 j/kg by afternoon. After some morning elevated convection, a weak surface trough associated with the passage of the upper level feature will lead to sufficient surface convergence for thunderstorm development by early to mid afternoon. There is some uncertainty as to how far west thunderstorm initiation will be. The RAP pushes the surface trough through Dodge City late this morning, suggesting that any afternoon storms would be confined to south central Kansas. We opted keep the highest thunderstorm chances southeast of Dodge City this afternoon. Highs today will be in the lower to middle 90s given partial sunshine. Winds will be weaker by tonight along with partly cloudy skies; and this should allow temperatures to fall into the upper 60s. .LONG TERM...(Saturday through Thursday) ISSUED AT 255 AM CDT FRI AUG 15 2014 For Saturday, a stalled out warm front will be just north of Dodge City. Some weak moisture convergence along this front may be enough to set off some scattered late afternoon thunderstorms and into the evening. Models show some moderate instability with CAPE over 2000 J/kg. Very weak upper level wind fields and lack of large scale dynamics should be enough to preclude a severe thunderstorm threat. Forecast soundings show an inverted V type sounding with some gusty winds to 50 mph the main threat. Highs will be warm and in the mid to upper 90s. Lows will be mild and in the upper 60s to around 70. On Sunday, weak upper level ridging continues across the Central Plains with a weak surface trough near Hays. With forecast moderate instability and some weak moisture convergence will continue with a slight chance of thunderstorms mainly near and north of Dodge City by later in the afternoon and overnight. The severe threat again looks minimal. Highs will continue in the mid to upper 90s with overnight lows in the upper 60s. For the period of Monday into Thursday of next week, a northern branch upper level wave moves across the Plains on Monday afternoon with a continued chance for thunderstorms. More weak upper level waves move across the Plains into Thursday with small chances for mainly late afternoon and evening thunderstorms. Highs continue in the mid 90s with lows in the upper 60s to around 70. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 141 PM CDT FRI AUG 15 2014 Light westerly surface wind with VFR flight conditions will persist as a mid level wave continues east through the region. Enhanced mid level frontogenesis will likely kick off a line of elevated thunderstorms later this afternoon, however these will likely be mainly east and south of DDC and HYS and will not be considered as a prevailing condition, but monitored for potential updates for VCTS is needed. && .PRELIMINARY POINT TEMPS/POPS... DDC 68 96 68 96 / 10 20 20 20 GCK 67 96 67 96 / 10 20 20 20 EHA 68 96 68 96 / 10 20 20 20 LBL 68 98 68 97 / 10 20 20 20 HYS 68 95 68 95 / 20 20 20 20 P28 71 98 70 97 / 10 10 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Finch LONG TERM...Kruse AVIATION...Russell
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
555 AM CDT Fri Aug 15 2014 ...Updated for Aviation... .SHORT TERM...(Today and tonight) ISSUED AT 347 AM CDT FRI AUG 15 2014 A weak shortwave trough was approaching western Kansas this morning. Ahead of this feature, elevated convection was ongoing near the interstate 70 corridor. This upper level feature will pass across southwest Kansas today. A narrow ribbon of low level moisture from El Paso into eastern Mew Mexico is expected to advect north-northeastward into southwest Kansas, leading to destabilization. Surface based CAPE values will approach 1500 j/kg by afternoon. After some morning elevated convection, a weak surface trough associated with the passage of the upper level feature will lead to sufficient surface convergence for thunderstorm development by early to mid afternoon. There is some uncertainty as to how far west thunderstorm initiation will be. The RAP pushes the surface trough through Dodge City late this morning, suggesting that any afternoon storms would be confined to south central Kansas. We opted keep the highest thunderstorm chances southeast of Dodge City this afternoon. Highs today will be in the lower to middle 90s given partial sunshine. Winds will be weaker by tonight along with partly cloudy skies; and this should allow temperatures to fall into the upper 60s. .LONG TERM...(Saturday through Thursday) ISSUED AT 255 AM CDT FRI AUG 15 2014 For Saturday, a stalled out warm front will be just north of Dodge City. Some weak moisture convergence along this front may be enough to set off some scattered late afternoon thunderstorms and into the evening. Models show some moderate instability with CAPE over 2000 J/kg. Very weak upper level wind fields and lack of large scale dynamics should be enough to preclude a severe thunderstorm threat. Forecast soundings show an inverted V type sounding with some gusty winds to 50 mph the main threat. Highs will be warm and in the mid to upper 90s. Lows will be mild and in the upper 60s to around 70. On Sunday, weak upper level ridging continues across the Central Plains with a weak surface trough near Hays. With forecast moderate instability and some weak moisture convergence will continue with a slight chance of thunderstorms mainly near and north of Dodge City by later in the afternoon and overnight. The severe threat again looks minimal. Highs will continue in the mid to upper 90s with overnight lows in the upper 60s. For the period of Monday into Thursday of next week, a northern branch upper level wave moves across the Plains on Monday afternoon with a continued chance for thunderstorms. More weak upper level waves move across the Plains into Thursday with small chances for mainly late afternoon and evening thunderstorms. Highs continue in the mid 90s with lows in the upper 60s to around 70. && .AVIATION...(For the 12Z TAFS through 12Z Saturday morning) ISSUED AT 551 AM CDT FRI AUG 15 2014 The upper level shortwave trough will be moving east this morning and taking any lingering showers and thunderstorms with it. At the surface a weak trough will move east across western Kansas today with light south to southwest winds shifting to light and variable after 19-21Z. VFR conditions will continue into tonight. && .PRELIMINARY POINT TEMPS/POPS... DDC 94 67 96 68 / 30 20 20 20 GCK 94 67 96 67 / 30 10 20 20 EHA 95 67 96 68 / 10 10 20 20 LBL 96 68 98 68 / 30 20 20 20 HYS 93 67 95 68 / 50 20 20 20 P28 95 69 98 70 / 30 30 10 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Finch LONG TERM...Kruse AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
402 AM CDT Fri Aug 15 2014 ...Updated for short term discussion... .SHORT TERM...(Today and tonight) ISSUED AT 347 AM CDT FRI AUG 15 2014 A weak shortwave trough was approaching western Kansas this morning. Ahead of this feature, elevated convection was ongoing near the interstate 70 corridor. This upper level feature will pass across southwest Kansas today. A narrow ribbon of low level moisture from El Paso into eastern Mew Mexico is expected to advect north-northeastward into southwest Kansas, leading to destabilization. Surface based CAPE values will approach 1500 j/kg by afternoon. After some morning elevated convection, a weak surface trough associated with the passage of the upper level feature will lead to sufficient surface convergence for thunderstorm development by early to mid afternoon. There is some uncertainty as to how far west thunderstorm initiation will be. The RAP pushes the surface trough through Dodge City late this morning, suggesting that any afternoon storms would be confined to south central Kansas. We opted keep the highest thunderstorm chances southeast of Dodge City this afternoon. Highs today will be in the lower to middle 90s given partial sunshine. Winds will be weaker by tonight along with partly cloudy skies; and this should allow temperatures to fall into the upper 60s. .LONG TERM...(Saturday through Thursday) ISSUED AT 255 AM CDT FRI AUG 15 2014 For Saturday, a stalled out warm front will be just north of Dodge City. Some weak moisture convergence along this front may be enough to set off some scattered late afternoon thunderstorms and into the evening. Models show some moderate instability with CAPE over 2000 J/kg. Very weak upper level wind fields and lack of large scale dynamics should be enough to preclude a severe thunderstorm threat. Forecast soundings show an inverted V type sounding with some gusty winds to 50 mph the main threat. Highs will be warm and in the mid to upper 90s. Lows will be mild and in the upper 60s to around 70. On Sunday, weak upper level ridging continues across the Central Plains with a weak surface trough near Hays. With forecast moderate instability and some weak moisture convergence will continue with a slight chance of thunderstorms mainly near and north of Dodge City by later in the afternoon and overnight. The severe threat again looks minimal. Highs will continue in the mid to upper 90s with overnight lows in the upper 60s. For the period of Monday into Thursday of next week, a northern branch upper level wave moves across the Plains on Monday afternoon with a continued chance for thunderstorms. More weak upper level waves move across the Plains into Thursday with small chances for mainly late afternoon and evening thunderstorms. Highs continue in the mid 90s with lows in the upper 60s to around 70. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1253 AM CDT FRI AUG 15 2014 A few thunderstorms are possible at KHYS through 09z ahead of an upper level disturbance. A weak frontal boundary will approach western Kansas on Friday, resulting in chances for thunderstorms after 20z at KHYS/KDDC. Outside of thunderstorms, VFR conditions can be expected along with south winds at 10-15 kts, shifting to the southwest after 15z and becoming light after 21z. && .PRELIMINARY POINT TEMPS/POPS... DDC 94 67 96 68 / 30 20 20 20 GCK 94 67 96 67 / 30 10 20 20 EHA 95 67 96 68 / 20 20 20 20 LBL 96 68 98 68 / 30 20 20 20 HYS 93 67 95 68 / 30 10 20 20 P28 95 69 98 70 / 30 30 10 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Finch LONG TERM...Kruse AVIATION...Finch
AREA FORECAST DISCUSSION
NWS JACKSON KY
330 PM EDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1215 PM EDT FRI AUG 15 2014 THE SLOW MOVING COLD FRONT THAT WORKED THROUGH THE REGION ON THU AFTERNOON AND THU NIGHT APPEARS TO HAVE MOVED SOUTH OF THE AREA PER THE WIND FIELDS. HOWEVER...A SECONDARY SFC TROUGH IS APPARENT IN VIS IMAGERY AND SFC WIND FIELDS FROM THE WV MOUNTAINS WEST TO JUST NORTH OF THE MTN PARKWAY AND WEST INTO CENTRAL KY. LOW CLOUDS HAVE PERSISTED IN THE BIG SANDY VALLEY...ESPECIALLY TUG FORK REGION THE LONGEST AND NEAR THIS SFC CONVERGENCE ZONE. TEMPS WHERE THE FOG AND LOW STRATUS HAS BEEN SLOWEST TO LIFT INTO STRATOCU AND CU HAVE REMAINED IN THE 60S SO FAR WHILE ELSEWHERE OUTSIDE OF THE HIGHEST TERRAIN TEMPS HAVE CLIMBED INTO THE 70S. HOURLY TEMPERATURE AND SKY GRIDS HAVE BEEN AND WILL CONTINUE TO BE ADJUSTED FOR THIS. OTHERWISE...A STRAY SHOWER ACROSS THE SOUTHERNMOST TIER OF COUNTIES CANNOT BE RULED OUT...FROM WAYNE COUNTY OVER TO HARLAN COUNTY. HOWEVER...GUIDANCE SEEMS TO HAVE TRENDED DOWN WITH THIS. THE HRRR WHICH DID A REASONABLY GOOD JOB WITH AFTERNOON AND EVENING CONVECTION ON THU HAS CONSISTENTLY KEPT ANY ACTIVITY FROM NEAR THE INTERSTATE 81 CORRIDOR OF VA/TN SOUTH AND EAST. AT THIS TIME...WE WILL CONTINUE WITH PERSISTENCE FROM THE PREVIOUS FORECAST FOR POPS. UPDATE ISSUED AT 755 AM EDT FRI AUG 15 2014 THE AREAS OF DENSE FOG REMAIN THE PRIMARY WEATHER ISSUE EARLY THIS MORNING WITH THE LOWEST VIS FOUND GENERALLY BETWEEN THE HAL ROGERS PARKWAY AND INTERSTATE 64. EXPECT THE FOG TO BREAK UP OVER THE NEXT HOUR OR SO WITH A PARTLY TO MOSTLY SUNNY DAY TO FOLLOW FOR MOST OF THE AREA. SO THIS UPDATE PRIMARILY JUST CONSISTS OF MATCHING THE OBS AND TRENDS FOR THE T AND TD GRIDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 345 AM EDT FRI AUG 15 2014 06Z SFC ANALYSIS SHOWS GENERALLY WEAK HIGH PRESSURE THROUGH THE OHIO AND TENNESSEE VALLEYS. A STALLED FRONTAL BOUNDARY EXISTS OVER PARTS OF CENTRAL AND EASTERN KENTUCKY. THIS IS RESPONSIBLE FOR THE EXTRA MOISTURE IN THE FORM OF SHOWERS AND SPRINKLES THAT SANK THROUGH THE CWA EARLIER IN THE EVENING. THE MOISTURE...FOLLOWED BY SOME CLEARING IN THE WAKE OF THE FRONT...HAS LED TO AREAS OF DENSE FOG...GENERALLY NORTH OF THE HAL ROGERS PARKWAY. AS THE NIGHT WEARS ON...EXPECT THE FOG AND DENSE PARTS OF IT TO SETTLE FURTHER SOUTH. ACCORDINGLY... HAVE ISSUED AN SPS AND A GRAPHICAST TO ADDRESS THE LOW VISIBILITIES. THESE RUN THROUGH 5 AM AND WILL LIKELY BE REISSUED THROUGH 9 AM SHOULD THE FOG NOT START TO DISSIPATE BY THEN. HOWEVER...OVER THE FAR NORTHERN PARTS OF THE AREA SOME DRIER AIR IS WORKING INTO OUR CWA AND SHOULD LIMIT THE FOG AND WITH TIME HELP TO CLEAR IT. SO WILL LIKELY TAKE THIS INTO CONSIDERATION WITH RESPECT TO THE FOG THREAT THROUGH THE REST OF THE NIGHT AND SPS OUTLINE. THE PROXIMITY OF THE FRONT HAS ALSO BROUGHT HIGHER DEWPOINTS TO THE AREA RESULTING IN A MILDER AND MORE UNIFORM TEMPERATURE NIGHT THAN INITIALLY ANTICIPATED. AS SUCH...TEMPS AND DEWPOINTS THROUGH THE AREA ARE GENERALLY IN THE LOWER 60S WITH A FEW POCKETS OF UPPER 50S ON THE FRINGES...AWAY FROM THE STALLED BOUNDARIES. THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH THE MAIN FEATURES THAT WILL AFFECT THE AREA THROUGH THE SHORT TERM. A BROAD AND DEEP UPPER LOW WILL CONTINUE TO MOVE NORTHEAST AND AWAY FROM THE REGION. IN ITS WAKE NORTHWEST FLOW WILL BRING A COUPLE WEAK MID LEVEL ENERGY PACKETS OVER KENTUCKY TONIGHT AND DURING THE DAY SATURDAY. FOR THIS...A GENERAL MODEL COMPROMISE IS PREFERRED WHILE THE HRRR AND NAM12 WAS GIVEN THE MOST WEIGHT FOR THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE AREAS OF DENSE FOG AROUND THIS MORNING AND THE RESIDUAL FRONT OVER THE SOUTHERN PORTION OF THE AREA. THIS FRONT WAS MORE PROLIFIC THAN EXPECTED DURING THE DAY AND EVENING ON THURSDAY. WITH THIS IN MIND WILL KEEP A SMALL CHANCE OF SPRINKLES AND SHOWERS IN THE FORECAST ACROSS THE SOUTH TODAY. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE WEST TONIGHT INTO SATURDAY AS THE FRONT STARTS TO MOVE BACK NORTHEAST. CANNOT RULE OUT A SHOWER WITH THIS LATER TONIGHT OR ON SATURDAY...BUT FOR NOW WILL KEEP IT DRY IN THE FORECAST GRIDS. TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL THROUGH SATURDAY THANKS IN PART TO THE EXTRA CLOUDS AROUND. AGAIN TONIGHT...PATCHY VALLEY FOG CAN BE EXPECTED TO DEVELOP AFTER MIDNIGHT...BUT LIKELY BE MITIGATED BY THE ADDITIONAL CLOUDS. STARTED WITH THE CONSSHORT FOR THE T/TD/WIND GRIDS THROUGH THE FIRST 24 HOURS AND USED THE SUPERBLEND FOR THE REST OF THE SHORT TERM. DID MAKE SOME ADJUSTMENTS TONIGHT FOR MINOR RIDGE AND VALLEY TEMPERATURE DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY ACROSS OUR SOUTHERN ZONES...OWING TO THE LINGERING FRONT. FOR THE REST OF THE FORECAST...WAS IN LINE WITH GUIDANCE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 328 PM EDT FRI AUG 15 2014 KY WILL BE TRANSITIONING FROM AN UPPER LEVEL TROUGHING PATTERN TO MORE ZONAL FLOW BY THE BEGINNING OF THE FORECAST PERIOD. SEVERAL SHORTWAVES ARE POISED TO MOVE THROUGH THIS LONGWAVE PATTERN DURING THE EXTENDED FORECAST PERIOD...IMPACTING MUCH OF KY. THE FIRST OF THESE SHORTWAVES WILL MOVE INTO THE REGION DURING THE DAY SUNDAY...WITH A COLD FRONT AND PRECIP CHANCES EXPECTED TO FOLLOW SUIT. THE GFS AND THE NAM ARE NOW THE MOST PROGRESSIVE...SHOWING PRECIP ENCOMPASSING ALL OF EASTERN KY BY 0Z MONDAY. THE ECMWF IS ABOUT 6 HOURS BEHIND...WHILE THE GEM IS MUCH MORE SCATTERED IN NATURE AND APPEARS TO BE THE OUTLIER OF THE MODELS. WILL KEEP CLOSER TO THE NAM AND GFS SOLUTIONS AT THIS TIME. A GOOD AREA OF CONVERGENCE WILL ACCOMPANY THE ONSET OF PRECIP THROUGH THE DAY SUNDAY...AS WILL DECENT LOW LEVEL SHEAR AND CAPE VALUES. EXPECT A GOOD CHANCE FOR THUNDERSTORMS THIS DAY...THOUGH SEVERE HAIL AND WIND THREAT SEEM FAIRLY LOW GIVEN THE SATURATION IN THE MID AND UPPER LEVELS AND THE LACK OF STRONG WINDS ALOFT. THE FIRST SHORT WAVE WILL SLOWLY PASS THROUGH SUNDAY INTO MONDAY NIGHT...WITH INCREASED CHANCES FOR CONVECTION ACROSS MUCH OF EASTERN KY DURING THE AFTERNOON HOURS WITH PEAK HEATING. WHILE BRIEF DRYING IS EXPECTED OVER THE WESTERN PORTION OF THE CWA MONDAY NIGHT...THIS WILL UNFORTUNATELY BE SHORT LIVED. ALTHOUGH THE SURFACE LOW AND SHORTWAVE WILL BE MOVING EASTWARD...THE SURFACE COLD FRONT WILL ELONGATE EASTWARD...BECOMING NEARLY STATIONARY WITH NO UPPER LEVEL FORCING TO PUSH IT OUT OF THE OHIO RIVER VALLEY REGION. LATEST ECMWF IS STILL POSITIONING THE STATIONARY FRONT JUST TO THE NORTH OF THE OHIO RIVER VALLEY FROM TUESDAY THROUGH THURSDAY...BEFORE FINALLY PULLING NORTHWARD DURING THE DAY FRIDAY. AS A RESULT...KY WILL FIND ITSELF IN THE WARM SECTOR...WITH GOOD WAA AND SEASONABLE OR WARMER HIGH TEMPS FOR WEDNESDAY THROUGH FRIDAY /GENERALLY IN THE MID AND UPPER 80S/. MOIST WARM FLOW OFF THE ATLANTIC...AND A GOOD BAROCLINIC ZONE/FRONTOGENESIS...WILL BE ENOUGH TO SPARK SHOWERS AND THUNDERSTORMS EACH DAY FOR THE REMAINDER OF THE FORECAST...MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS...BEFORE FINALLY TAPERING OFF ACROSS SOUTHERN KY DURING THE DAY FRIDAY. ALLBLEND GAVE HIGHER END CHANCES FOR DURING THE DAY FRIDAY THAT WHAT WAS WARRANTED GIVEN THE LIFTING FRONT...SO DROPPED THEM BACK TO SLIGHT CHANCES AND LOW END CHANCES...TAPERING OFF LATE IN THE AFTERNOON FRIDAY. THE GULF FLOW AND A NEARBY BOUNDARY WILL BE ENOUGH TO KEEP CLOUD COVER ACROSS THE CWA DURING MUCH OF THE FORECAST PERIOD. THIS...ALONG WITH ZONAL FLOW AND ONGOING PRECIP...WILL HELP TO HAMPER TEMPS FROM REACHING THEIR MAX AND MIX POTENTIAL DURING THE EXTENDED. HIGHS...AS MENTIONED ABOVE...WILL REMAIN IN THE 80S WITH HIGH HUMIDITY POSSIBLE. MEANWHILE OVERNIGHT LOWS...WITH LACK OF MAX RADIATIONAL COOLING...WILL REMAIN IN THE UPPER 60S TO AROUND 70. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 155 PM EDT FRI AUG 15 2014 A SLOW MOVING BOUNDARY HAS MOVED/MIXED SOUTH ACROSS THE NORTHERN TWO THIRDS OF THE CWA. THE THREAT FOR A STRAY SHOWER WILL REMAIN ACROSS THE HIGHEST TERRAIN THROUGH 21Z...BUT THIS WILL NOT AFFECT THE TAF SITES... AS THE BOUNDARY AND SECONDARY TROUGH CONTINUE TO SLOWLY SAG INTO THE TN VALLEYS. AREAS OF FOG...POSSIBLY DENSE AT SEVERAL OF THE TAF SITES... CAN BE ANTICIPATED GENERALLY 4Z TO 14Z. THIS WILL AFFECT THE TAF SITES TO VARYING DEGREES. MOS GUIDANCE AND LAMP GUIDANCE HITS THIS RATHER HARD AT JKL...LOZ AND SME AND PERSISTENCE WAS BLENDED INTO THIS THINKING FOR A FORECAST OF TIMING WITH SJS LIKELY TO BE AFFECTED AS WELL. LOCATIONS NORTH OF THE MTN PARKWAY SHOULD BE LEAST AFFECTED DUE TO A DRIER AIRMASS THERE. WINDS THROUGH THE PERIOD WILL CONTINUE TO BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...JMW AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
206 PM EDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1215 PM EDT FRI AUG 15 2014 THE SLOW MOVING COLD FRONT THAT WORKED THROUGH THE REGION ON THU AFTERNOON AND THU NIGHT APPEARS TO HAVE MOVED SOUTH OF THE AREA PER THE WIND FIELDS. HOWEVER...A SECONDARY SFC TROUGH IS APPARENT IN VIS IMAGERY AND SFC WIND FIELDS FROM THE WV MOUNTAINS WEST TO JUST NORTH OF THE MTN PARKWAY AND WEST INTO CENTRAL KY. LOW CLOUDS HAVE PERSISTED IN THE BIG SANDY VALLEY...ESPECIALLY TUG FORK REGION THE LONGEST AND NEAR THIS SFC CONVERGENCE ZONE. TEMPS WHERE THE FOG AND LOW STRATUS HAS BEEN SLOWEST TO LIFT INTO STRATOCU AND CU HAVE REMAINED IN THE 60S SO FAR WHILE ELSEWHERE OUTSIDE OF THE HIGHEST TERRAIN TEMPS HAVE CLIMBED INTO THE 70S. HOURLY TEMPERATURE AND SKY GRIDS HAVE BEEN AND WILL CONTINUE TO BE ADJUSTED FOR THIS. OTHERWISE...A STRAY SHOWER ACROSS THE SOUTHERNMOST TIER OF COUNTIES CANNOT BE RULED OUT...FROM WAYNE COUNTY OVER TO HARLAN COUNTY. HOWEVER...GUIDANCE SEEMS TO HAVE TRENDED DOWN WITH THIS. THE HRRR WHICH DID A REASONABLY GOOD JOB WITH AFTERNOON AND EVENING CONVECTION ON THU HAS CONSISTENTLY KEPT ANY ACTIVITY FROM NEAR THE INTERSTATE 81 CORRIDOR OF VA/TN SOUTH AND EAST. AT THIS TIME...WE WILL CONTINUE WITH PERSISTENCE FROM THE PREVIOUS FORECAST FOR POPS. UPDATE ISSUED AT 755 AM EDT FRI AUG 15 2014 THE AREAS OF DENSE FOG REMAIN THE PRIMARY WEATHER ISSUE EARLY THIS MORNING WITH THE LOWEST VIS FOUND GENERALLY BETWEEN THE HAL ROGERS PARKWAY AND INTERSTATE 64. EXPECT THE FOG TO BREAK UP OVER THE NEXT HOUR OR SO WITH A PARTLY TO MOSTLY SUNNY DAY TO FOLLOW FOR MOST OF THE AREA. SO THIS UPDATE PRIMARILY JUST CONSISTS OF MATCHING THE OBS AND TRENDS FOR THE T AND TD GRIDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 345 AM EDT FRI AUG 15 2014 06Z SFC ANALYSIS SHOWS GENERALLY WEAK HIGH PRESSURE THROUGH THE OHIO AND TENNESSEE VALLEYS. A STALLED FRONTAL BOUNDARY EXISTS OVER PARTS OF CENTRAL AND EASTERN KENTUCKY. THIS IS RESPONSIBLE FOR THE EXTRA MOISTURE IN THE FORM OF SHOWERS AND SPRINKLES THAT SANK THROUGH THE CWA EARLIER IN THE EVENING. THE MOISTURE...FOLLOWED BY SOME CLEARING IN THE WAKE OF THE FRONT...HAS LED TO AREAS OF DENSE FOG...GENERALLY NORTH OF THE HAL ROGERS PARKWAY. AS THE NIGHT WEARS ON...EXPECT THE FOG AND DENSE PARTS OF IT TO SETTLE FURTHER SOUTH. ACCORDINGLY... HAVE ISSUED AN SPS AND A GRAPHICAST TO ADDRESS THE LOW VISIBILITIES. THESE RUN THROUGH 5 AM AND WILL LIKELY BE REISSUED THROUGH 9 AM SHOULD THE FOG NOT START TO DISSIPATE BY THEN. HOWEVER...OVER THE FAR NORTHERN PARTS OF THE AREA SOME DRIER AIR IS WORKING INTO OUR CWA AND SHOULD LIMIT THE FOG AND WITH TIME HELP TO CLEAR IT. SO WILL LIKELY TAKE THIS INTO CONSIDERATION WITH RESPECT TO THE FOG THREAT THROUGH THE REST OF THE NIGHT AND SPS OUTLINE. THE PROXIMITY OF THE FRONT HAS ALSO BROUGHT HIGHER DEWPOINTS TO THE AREA RESULTING IN A MILDER AND MORE UNIFORM TEMPERATURE NIGHT THAN INITIALLY ANTICIPATED. AS SUCH...TEMPS AND DEWPOINTS THROUGH THE AREA ARE GENERALLY IN THE LOWER 60S WITH A FEW POCKETS OF UPPER 50S ON THE FRINGES...AWAY FROM THE STALLED BOUNDARIES. THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH THE MAIN FEATURES THAT WILL AFFECT THE AREA THROUGH THE SHORT TERM. A BROAD AND DEEP UPPER LOW WILL CONTINUE TO MOVE NORTHEAST AND AWAY FROM THE REGION. IN ITS WAKE NORTHWEST FLOW WILL BRING A COUPLE WEAK MID LEVEL ENERGY PACKETS OVER KENTUCKY TONIGHT AND DURING THE DAY SATURDAY. FOR THIS...A GENERAL MODEL COMPROMISE IS PREFERRED WHILE THE HRRR AND NAM12 WAS GIVEN THE MOST WEIGHT FOR THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE AREAS OF DENSE FOG AROUND THIS MORNING AND THE RESIDUAL FRONT OVER THE SOUTHERN PORTION OF THE AREA. THIS FRONT WAS MORE PROLIFIC THAN EXPECTED DURING THE DAY AND EVENING ON THURSDAY. WITH THIS IN MIND WILL KEEP A SMALL CHANCE OF SPRINKLES AND SHOWERS IN THE FORECAST ACROSS THE SOUTH TODAY. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE WEST TONIGHT INTO SATURDAY AS THE FRONT STARTS TO MOVE BACK NORTHEAST. CANNOT RULE OUT A SHOWER WITH THIS LATER TONIGHT OR ON SATURDAY...BUT FOR NOW WILL KEEP IT DRY IN THE FORECAST GRIDS. TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL THROUGH SATURDAY THANKS IN PART TO THE EXTRA CLOUDS AROUND. AGAIN TONIGHT...PATCHY VALLEY FOG CAN BE EXPECTED TO DEVELOP AFTER MIDNIGHT...BUT LIKELY BE MITIGATED BY THE ADDITIONAL CLOUDS. STARTED WITH THE CONSSHORT FOR THE T/TD/WIND GRIDS THROUGH THE FIRST 24 HOURS AND USED THE SUPERBLEND FOR THE REST OF THE SHORT TERM. DID MAKE SOME ADJUSTMENTS TONIGHT FOR MINOR RIDGE AND VALLEY TEMPERATURE DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY ACROSS OUR SOUTHERN ZONES...OWING TO THE LINGERING FRONT. FOR THE REST OF THE FORECAST...WAS IN LINE WITH GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 340 AM EDT FRI AUG 15 2014 THE EXTENDED FORECAST BEGINS ON SATURDAY NIGHT WITH THE UPPER LEVEL PATTERN BEGINNING TO BREAK DOWN AND UPPER LEVEL FEATURES MOVING ALONG A BIT FASTER. THROUGH THE PERIOD...NUMEROUS UPPER LEVEL SHORTWAVES WILL MOVE THROUGH THE OH RIVER VALLEY AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL AND MAINTAINS THIS PATTERN THROUGH THE ENTIRE EXTENDED. IN THE LOWER LEVELS...THE MORE POTENT FEATURE WILL BE THE SURFACE LOW MOVING THROUGH ON MONDAY WITH PLENTY OF SURFACE BASED INSTABILITY AND UPPER LEVEL SUPPORT. THIS DAY WILL BE A SCENARIO TO MONITOR AS SEVERE WEATHER IS POSSIBLE BUT WITH A LACK OF CONFIDENCE...CERTAINLY NOT SOMETHING TO HIGHLIGHT AT THIS POINT. ALSO...THE FORECAST PROBLEM HERE WILL BE TIMING...ESPECIALLY WITH A TRANSITIONS TO A MORE ZONAL PATTERN. FOR THE REST OF THE EXTENDED...SOUTHERLY FLOW WITH A SURFACE STATIONARY BOUNDARY SETTING UP ALONG THE LOWER OH VALLEY WILL ALLOW FOR MAINLY AFTERNOON AND EVENING CONVECTION THROUGH THE TUESDAY TO THURSDAY PERIOD. THIS APPEARS TO BE THE SET UP BUT THE GFS AND EURO STILL SHOW SOME DIFFERENCES IN THEIR SOLUTIONS. ALSO KEEPING IN MIND...THAT MODELS DO HAVE TROUBLE WITH TRANSITION PERIODS IN THE UPPER LEVEL FLOW. THIS IN MIND...DID STAY WITH THE MODEL ALL BLEND SOLUTION...EVEN LOWERED POPS SLIGHTLY BELOW THAT VALUE IN THE EXTENDED BASED UPON LACK OF CONFIDENCE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 155 PM EDT FRI AUG 15 2014 A SLOW MOVING BOUNDARY HAS MOVED/MIXED SOUTH ACROSS THE NORTHERN TWO THIRDS OF THE CWA. THE THREAT FOR A STRAY SHOWER WILL REMAIN ACROSS THE HIGHEST TERRAIN THROUGH 21Z...BUT THIS WILL NOT AFFECT THE TAF SITES... AS THE BOUNDARY AND SECONDARY TROUGH CONTINUE TO SLOWLY SAG INTO THE TN VALLEYS. AREAS OF FOG...POSSIBLY DENSE AT SEVERAL OF THE TAF SITES... CAN BE ANTICIPATED GENERALLY 4Z TO 14Z. THIS WILL AFFECT THE TAF SITES TO VARYING DEGREES. MOS GUIDANCE AND LAMP GUIDANCE HITS THIS RATHER HARD AT JKL...LOZ AND SME AND PERSISTENCE WAS BLENDED INTO THIS THINKING FOR A FORECAST OF TIMING WITH SJS LIKELY TO BE AFFECTED AS WELL. LOCATIONS NORTH OF THE MTN PARKWAY SHOULD BE LEAST AFFECTED DUE TO A DRIER AIRMASS THERE. WINDS THROUGH THE PERIOD WILL CONTINUE TO BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1241 PM EDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1215 PM EDT FRI AUG 15 2014 THE SLOW MOVING COLD FRONT THAT WORKED THROUGH THE REGION ON THU AFTERNOON AND THU NIGHT APPEARS TO HAVE MOVED SOUTH OF THE AREA PER THE WIND FIELDS. HOWEVER...A SECONDARY SFC TROUGH IS APPARENT IN VIS IMAGERY AND SFC WIND FIELDS FROM THE WV MOUNTAINS WEST TO JUST NORTH OF THE MTN PARKWAY AND WEST INTO CENTRAL KY. LOW CLOUDS HAVE PERSISTED IN THE BIG SANDY VALLEY...ESPECIALLY TUG FORK REGION THE LONGEST AND NEAR THIS SFC CONVERGENCE ZONE. TEMPS WHERE THE FOG AND LOW STRATUS HAS BEEN SLOWEST TO LIFT INTO STRATOCU AND CU HAVE REMAINED IN THE 60S SO FAR WHILE ELSEWHERE OUTSIDE OF THE HIGHEST TERRAIN TEMPS HAVE CLIMBED INTO THE 70S. HOURLY TEMPERATURE AND SKY GRIDS HAVE BEEN AND WILL CONTINUE TO BE ADJUSTED FOR THIS. OTHERWISE...A STRAY SHOWER ACROSS THE SOUTHERNMOST TIER OF COUNTIES CANNOT BE RULED OUT...FROM WAYNE COUNTY OVER TO HARLAN COUNTY. HOWEVER...GUIDANCE SEEMS TO HAVE TRENDED DOWN WITH THIS. THE HRRR WHICH DID A REASONABLY GOOD JOB WITH AFTERNOON AND EVENING CONVECTION ON THU HAS CONSISTENTLY KEPT ANY ACTIVITY FROM NEAR THE INTERSTATE 81 CORRIDOR OF VA/TN SOUTH AND EAST. AT THIS TIME...WE WILL CONTINUE WITH PERSISTENCE FROM THE PREVIOUS FORECAST FOR POPS. UPDATE ISSUED AT 755 AM EDT FRI AUG 15 2014 THE AREAS OF DENSE FOG REMAIN THE PRIMARY WEATHER ISSUE EARLY THIS MORNING WITH THE LOWEST VIS FOUND GENERALLY BETWEEN THE HAL ROGERS PARKWAY AND INTERSTATE 64. EXPECT THE FOG TO BREAK UP OVER THE NEXT HOUR OR SO WITH A PARTLY TO MOSTLY SUNNY DAY TO FOLLOW FOR MOST OF THE AREA. SO THIS UPDATE PRIMARILY JUST CONSISTS OF MATCHING THE OBS AND TRENDS FOR THE T AND TD GRIDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 345 AM EDT FRI AUG 15 2014 06Z SFC ANALYSIS SHOWS GENERALLY WEAK HIGH PRESSURE THROUGH THE OHIO AND TENNESSEE VALLEYS. A STALLED FRONTAL BOUNDARY EXISTS OVER PARTS OF CENTRAL AND EASTERN KENTUCKY. THIS IS RESPONSIBLE FOR THE EXTRA MOISTURE IN THE FORM OF SHOWERS AND SPRINKLES THAT SANK THROUGH THE CWA EARLIER IN THE EVENING. THE MOISTURE...FOLLOWED BY SOME CLEARING IN THE WAKE OF THE FRONT...HAS LED TO AREAS OF DENSE FOG...GENERALLY NORTH OF THE HAL ROGERS PARKWAY. AS THE NIGHT WEARS ON...EXPECT THE FOG AND DENSE PARTS OF IT TO SETTLE FURTHER SOUTH. ACCORDINGLY... HAVE ISSUED AN SPS AND A GRAPHICAST TO ADDRESS THE LOW VISIBILITIES. THESE RUN THROUGH 5 AM AND WILL LIKELY BE REISSUED THROUGH 9 AM SHOULD THE FOG NOT START TO DISSIPATE BY THEN. HOWEVER...OVER THE FAR NORTHERN PARTS OF THE AREA SOME DRIER AIR IS WORKING INTO OUR CWA AND SHOULD LIMIT THE FOG AND WITH TIME HELP TO CLEAR IT. SO WILL LIKELY TAKE THIS INTO CONSIDERATION WITH RESPECT TO THE FOG THREAT THROUGH THE REST OF THE NIGHT AND SPS OUTLINE. THE PROXIMITY OF THE FRONT HAS ALSO BROUGHT HIGHER DEWPOINTS TO THE AREA RESULTING IN A MILDER AND MORE UNIFORM TEMPERATURE NIGHT THAN INITIALLY ANTICIPATED. AS SUCH...TEMPS AND DEWPOINTS THROUGH THE AREA ARE GENERALLY IN THE LOWER 60S WITH A FEW POCKETS OF UPPER 50S ON THE FRINGES...AWAY FROM THE STALLED BOUNDARIES. THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH THE MAIN FEATURES THAT WILL AFFECT THE AREA THROUGH THE SHORT TERM. A BROAD AND DEEP UPPER LOW WILL CONTINUE TO MOVE NORTHEAST AND AWAY FROM THE REGION. IN ITS WAKE NORTHWEST FLOW WILL BRING A COUPLE WEAK MID LEVEL ENERGY PACKETS OVER KENTUCKY TONIGHT AND DURING THE DAY SATURDAY. FOR THIS...A GENERAL MODEL COMPROMISE IS PREFERRED WHILE THE HRRR AND NAM12 WAS GIVEN THE MOST WEIGHT FOR THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE AREAS OF DENSE FOG AROUND THIS MORNING AND THE RESIDUAL FRONT OVER THE SOUTHERN PORTION OF THE AREA. THIS FRONT WAS MORE PROLIFIC THAN EXPECTED DURING THE DAY AND EVENING ON THURSDAY. WITH THIS IN MIND WILL KEEP A SMALL CHANCE OF SPRINKLES AND SHOWERS IN THE FORECAST ACROSS THE SOUTH TODAY. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE WEST TONIGHT INTO SATURDAY AS THE FRONT STARTS TO MOVE BACK NORTHEAST. CANNOT RULE OUT A SHOWER WITH THIS LATER TONIGHT OR ON SATURDAY...BUT FOR NOW WILL KEEP IT DRY IN THE FORECAST GRIDS. TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL THROUGH SATURDAY THANKS IN PART TO THE EXTRA CLOUDS AROUND. AGAIN TONIGHT...PATCHY VALLEY FOG CAN BE EXPECTED TO DEVELOP AFTER MIDNIGHT...BUT LIKELY BE MITIGATED BY THE ADDITIONAL CLOUDS. STARTED WITH THE CONSSHORT FOR THE T/TD/WIND GRIDS THROUGH THE FIRST 24 HOURS AND USED THE SUPERBLEND FOR THE REST OF THE SHORT TERM. DID MAKE SOME ADJUSTMENTS TONIGHT FOR MINOR RIDGE AND VALLEY TEMPERATURE DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY ACROSS OUR SOUTHERN ZONES...OWING TO THE LINGERING FRONT. FOR THE REST OF THE FORECAST...WAS IN LINE WITH GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 340 AM EDT FRI AUG 15 2014 THE EXTENDED FORECAST BEGINS ON SATURDAY NIGHT WITH THE UPPER LEVEL PATTERN BEGINNING TO BREAK DOWN AND UPPER LEVEL FEATURES MOVING ALONG A BIT FASTER. THROUGH THE PERIOD...NUMEROUS UPPER LEVEL SHORTWAVES WILL MOVE THROUGH THE OH RIVER VALLEY AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL AND MAINTAINS THIS PATTERN THROUGH THE ENTIRE EXTENDED. IN THE LOWER LEVELS...THE MORE POTENT FEATURE WILL BE THE SURFACE LOW MOVING THROUGH ON MONDAY WITH PLENTY OF SURFACE BASED INSTABILITY AND UPPER LEVEL SUPPORT. THIS DAY WILL BE A SCENARIO TO MONITOR AS SEVERE WEATHER IS POSSIBLE BUT WITH A LACK OF CONFIDENCE...CERTAINLY NOT SOMETHING TO HIGHLIGHT AT THIS POINT. ALSO...THE FORECAST PROBLEM HERE WILL BE TIMING...ESPECIALLY WITH A TRANSITIONS TO A MORE ZONAL PATTERN. FOR THE REST OF THE EXTENDED...SOUTHERLY FLOW WITH A SURFACE STATIONARY BOUNDARY SETTING UP ALONG THE LOWER OH VALLEY WILL ALLOW FOR MAINLY AFTERNOON AND EVENING CONVECTION THROUGH THE TUESDAY TO THURSDAY PERIOD. THIS APPEARS TO BE THE SET UP BUT THE GFS AND EURO STILL SHOW SOME DIFFERENCES IN THEIR SOLUTIONS. ALSO KEEPING IN MIND...THAT MODELS DO HAVE TROUBLE WITH TRANSITION PERIODS IN THE UPPER LEVEL FLOW. THIS IN MIND...DID STAY WITH THE MODEL ALL BLEND SOLUTION...EVEN LOWERED POPS SLIGHTLY BELOW THAT VALUE IN THE EXTENDED BASED UPON LACK OF CONFIDENCE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 800 AM EDT FRI AUG 15 2014 A STALLED OUT BOUNDARY LINGERS OVER EASTERN KENTUCKY FOR THE NEXT 24 TO 36 HOURS. THIS BOUNDARY HAS LED TO PRETTY GOOD FOG FORMATION FOR MUCH OF THE AREA EARLY THIS MORNING. THE FOG WILL BURN OFF BETWEEN 12 AND 14Z AT THE TAF SITES. THE THREAT OF MORE SHOWERS WILL REMAIN ACROSS THE SOUTH THIS AFTERNOON AS THE BOUNDARY CONTINUES TO SLOWLY SAG SOUTHWARD. PATCHY FOG...LOCALLY DENSE...CAN BE ANTICIPATED AGAIN LATE TONIGHT FOR THE TAF SITES. WINDS THROUGH THE PERIOD WILL CONTINUE TO BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
800 AM EDT FRI AUG 15 2014 .UPDATE... ISSUED AT 755 AM EDT FRI AUG 15 2014 THE AREAS OF DENSE FOG REMAIN THE PRIMARY WEATHER ISSUE EARLY THIS MORNING WITH THE LOWEST VIS FOUND GENERALLY BETWEEN THE HAL ROGERS PARKWAY AND INTERSTATE 64. EXPECT THE FOG TO BREAK UP OVER THE NEXT HOUR OR SO WITH A PARTLY TO MOSTLY SUNNY DAY TO FOLLOW FOR MOST OF THE AREA. SO THIS UPDATE PRIMARILY JUST CONSISTS OF MATCHING THE OBS AND TRENDS FOR THE T AND TD GRIDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 345 AM EDT FRI AUG 15 2014 06Z SFC ANALYSIS SHOWS GENERALLY WEAK HIGH PRESSURE THROUGH THE OHIO AND TENNESSEE VALLEYS. A STALLED FRONTAL BOUNDARY EXISTS OVER PARTS OF CENTRAL AND EASTERN KENTUCKY. THIS IS RESPONSIBLE FOR THE EXTRA MOISTURE IN THE FORM OF SHOWERS AND SPRINKLES THAT SANK THROUGH THE CWA EARLIER IN THE EVENING. THE MOISTURE...FOLLOWED BY SOME CLEARING IN THE WAKE OF THE FRONT...HAS LED TO AREAS OF DENSE FOG...GENERALLY NORTH OF THE HAL ROGERS PARKWAY. AS THE NIGHT WEARS ON...EXPECT THE FOG AND DENSE PARTS OF IT TO SETTLE FURTHER SOUTH. ACCORDINGLY... HAVE ISSUED AN SPS AND A GRAPHICAST TO ADDRESS THE LOW VISIBILITIES. THESE RUN THROUGH 5 AM AND WILL LIKELY BE REISSUED THROUGH 9 AM SHOULD THE FOG NOT START TO DISSIPATE BY THEN. HOWEVER...OVER THE FAR NORTHERN PARTS OF THE AREA SOME DRIER AIR IS WORKING INTO OUR CWA AND SHOULD LIMIT THE FOG AND WITH TIME HELP TO CLEAR IT. SO WILL LIKELY TAKE THIS INTO CONSIDERATION WITH RESPECT TO THE FOG THREAT THROUGH THE REST OF THE NIGHT AND SPS OUTLINE. THE PROXIMITY OF THE FRONT HAS ALSO BROUGHT HIGHER DEWPOINTS TO THE AREA RESULTING IN A MILDER AND MORE UNIFORM TEMPERATURE NIGHT THAN INITIALLY ANTICIPATED. AS SUCH...TEMPS AND DEWPOINTS THROUGH THE AREA ARE GENERALLY IN THE LOWER 60S WITH A FEW POCKETS OF UPPER 50S ON THE FRINGES...AWAY FROM THE STALLED BOUNDARIES. THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH THE MAIN FEATURES THAT WILL AFFECT THE AREA THROUGH THE SHORT TERM. A BROAD AND DEEP UPPER LOW WILL CONTINUE TO MOVE NORTHEAST AND AWAY FROM THE REGION. IN ITS WAKE NORTHWEST FLOW WILL BRING A COUPLE WEAK MID LEVEL ENERGY PACKETS OVER KENTUCKY TONIGHT AND DURING THE DAY SATURDAY. FOR THIS...A GENERAL MODEL COMPROMISE IS PREFERRED WHILE THE HRRR AND NAM12 WAS GIVEN THE MOST WEIGHT FOR THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE AREAS OF DENSE FOG AROUND THIS MORNING AND THE RESIDUAL FRONT OVER THE SOUTHERN PORTION OF THE AREA. THIS FRONT WAS MORE PROLIFIC THAN EXPECTED DURING THE DAY AND EVENING ON THURSDAY. WITH THIS IN MIND WILL KEEP A SMALL CHANCE OF SPRINKLES AND SHOWERS IN THE FORECAST ACROSS THE SOUTH TODAY. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE WEST TONIGHT INTO SATURDAY AS THE FRONT STARTS TO MOVE BACK NORTHEAST. CANNOT RULE OUT A SHOWER WITH THIS LATER TONIGHT OR ON SATURDAY...BUT FOR NOW WILL KEEP IT DRY IN THE FORECAST GRIDS. TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL THROUGH SATURDAY THANKS IN PART TO THE EXTRA CLOUDS AROUND. AGAIN TONIGHT...PATCHY VALLEY FOG CAN BE EXPECTED TO DEVELOP AFTER MIDNIGHT...BUT LIKELY BE MITIGATED BY THE ADDITIONAL CLOUDS. STARTED WITH THE CONSSHORT FOR THE T/TD/WIND GRIDS THROUGH THE FIRST 24 HOURS AND USED THE SUPERBLEND FOR THE REST OF THE SHORT TERM. DID MAKE SOME ADJUSTMENTS TONIGHT FOR MINOR RIDGE AND VALLEY TEMPERATURE DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY ACROSS OUR SOUTHERN ZONES...OWING TO THE LINGERING FRONT. FOR THE REST OF THE FORECAST...WAS IN LINE WITH GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 340 AM EDT FRI AUG 15 2014 THE EXTENDED FORECAST BEGINS ON SATURDAY NIGHT WITH THE UPPER LEVEL PATTERN BEGINNING TO BREAK DOWN AND UPPER LEVEL FEATURES MOVING ALONG A BIT FASTER. THROUGH THE PERIOD...NUMEROUS UPPER LEVEL SHORTWAVES WILL MOVE THROUGH THE OH RIVER VALLEY AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL AND MAINTAINS THIS PATTERN THROUGH THE ENTIRE EXTENDED. IN THE LOWER LEVELS...THE MORE POTENT FEATURE WILL BE THE SURFACE LOW MOVING THROUGH ON MONDAY WITH PLENTY OF SURFACE BASED INSTABILITY AND UPPER LEVEL SUPPORT. THIS DAY WILL BE A SCENARIO TO MONITOR AS SEVERE WEATHER IS POSSIBLE BUT WITH A LACK OF CONFIDENCE...CERTAINLY NOT SOMETHING TO HIGHLIGHT AT THIS POINT. ALSO...THE FORECAST PROBLEM HERE WILL BE TIMING...ESPECIALLY WITH A TRANSITIONS TO A MORE ZONAL PATTERN. FOR THE REST OF THE EXTENDED...SOUTHERLY FLOW WITH A SURFACE STATIONARY BOUNDARY SETTING UP ALONG THE LOWER OH VALLEY WILL ALLOW FOR MAINLY AFTERNOON AND EVENING CONVECTION THROUGH THE TUESDAY TO THURSDAY PERIOD. THIS APPEARS TO BE THE SET UP BUT THE GFS AND EURO STILL SHOW SOME DIFFERENCES IN THEIR SOLUTIONS. ALSO KEEPING IN MIND...THAT MODELS DO HAVE TROUBLE WITH TRANSITION PERIODS IN THE UPPER LEVEL FLOW. THIS IN MIND...DID STAY WITH THE MODEL ALL BLEND SOLUTION...EVEN LOWERED POPS SLIGHTLY BELOW THAT VALUE IN THE EXTENDED BASED UPON LACK OF CONFIDENCE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 800 AM EDT FRI AUG 15 2014 A STALLED OUT BOUNDARY LINGERS OVER EASTERN KENTUCKY FOR THE NEXT 24 TO 36 HOURS. THIS BOUNDARY HAS LED TO PRETTY GOOD FOG FORMATION FOR MUCH OF THE AREA EARLY THIS MORNING. THE FOG WILL BURN OFF BETWEEN 12 AND 14Z AT THE TAF SITES. THE THREAT OF MORE SHOWERS WILL REMAIN ACROSS THE SOUTH THIS AFTERNOON AS THE BOUNDARY CONTINUES TO SLOWLY SAG SOUTHWARD. PATCHY FOG...LOCALLY DENSE...CAN BE ANTICIPATED AGAIN LATE TONIGHT FOR THE TAF SITES. WINDS THROUGH THE PERIOD WILL CONTINUE TO BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
345 AM EDT FRI AUG 15 2014 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 345 AM EDT FRI AUG 15 2014 06Z SFC ANALYSIS SHOWS GENERALLY WEAK HIGH PRESSURE THROUGH THE OHIO AND TENNESSEE VALLEYS. A STALLED FRONTAL BOUNDARY EXISTS OVER PARTS OF CENTRAL AND EASTERN KENTUCKY. THIS IS RESPONSIBLE FOR THE EXTRA MOISTURE IN THE FORM OF SHOWERS AND SPRINKLES THAT SANK THROUGH THE CWA EARLIER IN THE EVENING. THE MOISTURE...FOLLOWED BY SOME CLEARING IN THE WAKE OF THE FRONT...HAS LED TO AREAS OF DENSE FOG...GENERALLY NORTH OF THE HAL ROGERS PARKWAY. AS THE NIGHT WEARS ON...EXPECT THE FOG AND DENSE PARTS OF IT TO SETTLE FURTHER SOUTH. ACCORDINGLY... HAVE ISSUED AN SPS AND A GRAPHICAST TO ADDRESS THE LOW VISIBILITIES. THESE RUN THROUGH 5 AM AND WILL LIKELY BE REISSUED THROUGH 9 AM SHOULD THE FOG NOT START TO DISSIPATE BY THEN. HOWEVER...OVER THE FAR NORTHERN PARTS OF THE AREA SOME DRIER AIR IS WORKING INTO OUR CWA AND SHOULD LIMIT THE FOG AND WITH TIME HELP TO CLEAR IT. SO WILL LIKELY TAKE THIS INTO CONSIDERATION WITH RESPECT TO THE FOG THREAT THROUGH THE REST OF THE NIGHT AND SPS OUTLINE. THE PROXIMITY OF THE FRONT HAS ALSO BROUGHT HIGHER DEWPOINTS TO THE AREA RESULTING IN A MILDER AND MORE UNIFORM TEMPERATURE NIGHT THAN INITIALLY ANTICIPATED. AS SUCH...TEMPS AND DEWPOINTS THROUGH THE AREA ARE GENERALLY IN THE LOWER 60S WITH A FEW POCKETS OF UPPER 50S ON THE FRINGES...AWAY FROM THE STALLED BOUNDARIES. THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH THE MAIN FEATURES THAT WILL AFFECT THE AREA THROUGH THE SHORT TERM. A BROAD AND DEEP UPPER LOW WILL CONTINUE TO MOVE NORTHEAST AND AWAY FROM THE REGION. IN ITS WAKE NORTHWEST FLOW WILL BRING A COUPLE WEAK MID LEVEL ENERGY PACKETS OVER KENTUCKY TONIGHT AND DURING THE DAY SATURDAY. FOR THIS...A GENERAL MODEL COMPROMISE IS PREFERRED WHILE THE HRRR AND NAM12 WAS GIVEN THE MOST WEIGHT FOR THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE AREAS OF DENSE FOG AROUND THIS MORNING AND THE RESIDUAL FRONT OVER THE SOUTHERN PORTION OF THE AREA. THIS FRONT WAS MORE PROLIFIC THAN EXPECTED DURING THE DAY AND EVENING ON THURSDAY. WITH THIS IN MIND WILL KEEP A SMALL CHANCE OF SPRINKLES AND SHOWERS IN THE FORECAST ACROSS THE SOUTH TODAY. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE WEST TONIGHT INTO SATURDAY AS THE FRONT STARTS TO MOVE BACK NORTHEAST. CANNOT RULE OUT A SHOWER WITH THIS LATER TONIGHT OR ON SATURDAY...BUT FOR NOW WILL KEEP IT DRY IN THE FORECAST GRIDS. TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL THROUGH SATURDAY THANKS IN PART TO THE EXTRA CLOUDS AROUND. AGAIN TONIGHT...PATCHY VALLEY FOG CAN BE EXPECTED TO DEVELOP AFTER MIDNIGHT...BUT LIKELY BE MITIGATED BY THE ADDITIONAL CLOUDS. STARTED WITH THE CONSSHORT FOR THE T/TD/WIND GRIDS THROUGH THE FIRST 24 HOURS AND USED THE SUPERBLEND FOR THE REST OF THE SHORT TERM. DID MAKE SOME ADJUSTMENTS TONIGHT FOR MINOR RIDGE AND VALLEY TEMPERATURE DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY ACROSS OUR SOUTHERN ZONES...OWING TO THE LINGERING FRONT. FOR THE REST OF THE FORECAST...WAS IN LINE WITH GUIDANCE. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 340 AM EDT FRI AUG 15 2014 THE EXTENDED FORECAST BEGINS ON SATURDAY NIGHT WITH THE UPPER LEVEL PATTERN BEGINNING TO BREAK DOWN AND UPPER LEVEL FEATURES MOVING ALONG A BIT FASTER. THROUGH THE PERIOD...NUMEROUS UPPER LEVEL SHORTWAVES WILL MOVE THROUGH THE OH RIVER VALLEY AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL AND MAINTAINS THIS PATTERN THROUGH THE ENTIRE EXTENDED. IN THE LOWER LEVELS...THE MORE POTENT FEATURE WILL BE THE SURFACE LOW MOVING THROUGH ON MONDAY WITH PLENTY OF SURFACE BASED INSTABILITY AND UPPER LEVEL SUPPORT. THIS DAY WILL BE A SCENARIO TO MONITOR AS SEVERE WEATHER IS POSSIBLE BUT WITH A LACK OF CONFIDENCE...CERTAINLY NOT SOMETHING TO HIGHLIGHT AT THIS POINT. ALSO...THE FORECAST PROBLEM HERE WILL BE TIMING...ESPECIALLY WITH A TRANSITIONS TO A MORE ZONAL PATTERN. FOR THE REST OF THE EXTENDED...SOUTHERLY FLOW WITH A SURFACE STATIONARY BOUNDARY SETTING UP ALONG THE LOWER OH VALLEY WILL ALLOW FOR MAINLY AFTERNOON AND EVENING CONVECTION THROUGH THE TUESDAY TO THURSDAY PERIOD. THIS APPEARS TO BE THE SET UP BUT THE GFS AND EURO STILL SHOW SOME DIFFERENCES IN THEIR SOLUTIONS. ALSO KEEPING IN MIND...THAT MODELS DO HAVE TROUBLE WITH TRANSITION PERIODS IN THE UPPER LEVEL FLOW. THIS IN MIND...DID STAY WITH THE MODEL ALL BLEND SOLUTION...EVEN LOWERED POPS SLIGHTLY BELOW THAT VALUE IN THE EXTENDED BASED UPON LACK OF CONFIDENCE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 200 AM EDT FRI AUG 15 2014 A STALLED OUT BOUNDARY WILL LINGER OVER EASTERN KENTUCKY OVER THE NEXT 24 TO 36 HOURS. THIS BOUNDARY WILL RESULT IN SLIGHTLY HIGHER DEWPOINTS...LEADING TO PRETTY GOOD FOG POTENTIAL THROUGH THE REST OF THE NIGHT. QUESTION REMAIN REGARDING HOW MUCH CLOUD COVER WILL LINGER OVER THE CWA INTO DAWN. FROM THIS...THERE MAY BE A NARROW CORRIDOR ACROSS EASTERN KENTUCKY WITH A BIT MORE CLOUD COVER HELPING TO KEEP THE WORST OF THE FOG AT BAY. HOWEVER...ANY AREAS THAT CLEAR WILL BE PRONE TO DENSE FOG...SO HAVE CONTINUED TO BE PESSIMISTIC WITH THE TAFS AND TOOK ALL VISIBILITIES BELOW AIRPORT MINIMUMS THROUGH THE REMAINDER OF THE NIGHT. THE FOG WILL BURN OFF TOMORROW MORNING WITH THE THREAT OF MORE SHOWERS ACROSS THE SOUTH IN THE AFTERNOON AS THE BOUNDARY CONTINUES TO SLOWLY SAG SOUTHWARD. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...KAS/GREIF
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
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 THETAE 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. UPDATE OUT SHORTLY...13. && .PREV DISCUSSION... /ISSUED 710 PM CDT SAT AUG 16 2014/ AVIATION... ISOLATED THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH THE OVERNIGHT HOURS...MAINLY IN THE I-30 CORRIDOR. OTHERWISE...LL MOISTURE CONTINUES TO INCREASE...AND MVFR/PATCHY IFR CIGS/VSBYS WILL BE POSSIBLE AROUND SUNRISE AS A RESULT. VFR CONDITIONS ARE EXPECTED TO RETURN BY MID MORNING. ADDITIONAL CONVECTION WILL BE POSSIBLE SUNDAY...MAINLY DURING PEAK HEATING...BUT COVERAGE IS EXPECTED TO BE TOO ISOLD IN NATURE TO MENTION WITH THE 00Z TAF ISSUANCE. /12/ && .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. && $$ 13
AREA FORECAST DISCUSSION
NWS CARIBOU ME
644 AM EDT FRI AUG 15 2014 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL REMAIN NORTHWEST OF MAINE THROUGH THE WEEKEND. AS A RESULT...UNSETTLED CONDITIONS WILL PERSIST ACROSS THE REGION RIGHT INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 630 AM UPDATE...DECIDED INCREASE THE FOG FOR THE ENTIRE CWA THROUGH THIS MORNING PER THE LATEST OBS. THE FOG WILL LIFT AND BURN OFF AFTER 8 AM THANKS TO THE SUN AND WARMING TEMPERATURES. PULLED BACK ON THE ARRIVAL OF CLOUDS AND SHOWER USING THE HRRR AND RAP WHICH APPEAR TO BE DOING QUITE WELL W/THE LATEST SET UP. WV SATELLITE SHOWED ONE DISTURBANCE MOVING INTO SOUTHERN QUEBEC ATTM WHICH WILL LIFT NORTH TODAY INCREASING THE CHANCE FOR SHOWERS. PREVIOUS DISCUSSION... UNSETTLED CONDITIONS THIS TERM W/ANOTHER ROUND OF SHOWERS EXPECTED. FOG WILL ALSO BE A CONCERN. THE 06Z SURFACE ANALYSIS SHOWED WEAK LOW PRES LIFTING ACROSS NEW BRUNSWICK W/THE OCCLUDED FRONT ACROSS NORTHERN MAINE. AREA OF SHOWERS ACROSS NEW BRUNSWICK MOVING NNW PER THE LATEST RADAR W/THE WESTERN EDGE JUST E OF THE MAINE BORDER. THE LATEST RAP AND HRRR 3KM DOING WELL W/THIS AREA AND THE PLACEMENT OF THE LOW AND FRONT. A BLEND OF THE THESE 2 MODELS SHOW THE WESTERN EDGE JUST SKIRTING THE MAINE-NEW BRUNSWICK BORDER THROUGH THIS MORNING AS THE BEST FORCING REMAINS WELL E AND SW OF THE REGION. OOZ UA AND SATELLITE WV IMAGERY SHOW CLOSED UPPER LOW SPINNING OVER QUEBEC W/SPOKES OF ENERGY ROTATING AROUND THE LOW. THE IMPULSE THAT IS FORECAST TO AFFECT OUR CWA WAS MOVING ACROSS NYS AND VT AND IS EXPECTED TO MOVE ACROSS THE REGION BY THIS AFTERNOON INTO THIS EVENING. SOME LLVL CONVERGENCE COMBINED W/SOME MID LEVEL SUPPORT WILL ALLOW FOR SHOWERS TO BREAK OUT MAINLY ACROSS THE NORTHERN AND CENTRAL AREAS. DECIDED TO GO W/CHANCE POPS(30-40%) FOR THIS AFTERNOON INTO TONIGHT BUT TRIMMED BACK THE QPF A BIT W/TOTALS THROUGH TONIGHT RUNNING LESS THAN 0.10". SOUNDINGS INDICATE SB/MUCAPES LESS THAN 150 JOULES TODAY INTO THE EVENING AND THEREFORE LEFT TSTMS OUT OF THE FORECAST. CLOUDS AND SHOWERS WILL HOLD DOWN TEMPERATURES W/READINGS WILL RUN INTO THE UPPER 60S ACROSS THE NORTH AND WEST WHILE CENTRAL AND DOWNEAST SHOULD SEE LOWER 70S. COOL FOR MID AUGUST. FOG HAS DEVELOPED THIS MORNING THANKS TO LIGHT WINDS/PARTIAL CLEARING AND A WET GROUND. THE FOG WAS THE MOST DENSE ACROSS THE COAST BUT PATCHY DENSE WILL BE NUISANCE THROUGH SUNRISE JUST ABOUT EVERYWHERE. DECIDED TO LEAVE FOG OUT NORTH OF THE DOWNEAST AND COASTAL AREAS TONIGHT DUE TO CLOUDS AND SHOWERS. ATTM, IT LOOKS AS THOUGH THE FOG ACROSS THE DOWNEAST AND THE COAST WILL BE PATCHY. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A UPPER LOW OVER NORTHERN QUEBEC AT THE START OF NEAR TERM PERIOD IS FORECAST TO DRIFT SLOWLY SOUTHEAST ACROSS NEW BRUNSWICK TO EASTERN NOVA SCOTIA BY THE END OF THE PERIOD. A NEW FRONTAL SYSTEM WILL MOVE FROM SRN MAINE TOWARDS THE EASTERN NOVA SCOTIA BY END OF THE PERIOD. UNSETTLE WEATHER WILL PERSIST ACROSS MAINE THROUGH THE PERIOD. LOADED USED HPC GRIDS FOR QPF...NAWAVE 4 FOR SEAS IN THE COASTAL WATERS...AND A BLEND OF NAM/GFS/GEM/ECMWF THROUGH THE PERIOD FOR ALL OTHER ELEMENTS. && .LONG TERM /MONDAY THROUGH THURSDAY/... AT THE START OF THE PERIOD AN UPPER LEVEL LOW WILL BE MOVING INTO THE WESTERN CANADIAN MARITIMES...HIGHER PRESSURE WILL BEGIN BUILDING INTO MAINE. THE RIDGE WILL SET ACROSS THE REGION AND REMAIN THROUGH THE END OF THE PERIOD. POSSIBLE SHOWERS ACROSS NRN MAINE TOWARDS THE END OF THE PERIOD AS LOWER PRESSURE BEGINS TO ERODE THE NORTHERN PORTIONS OF THE RIDGE. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR/IFR THIS MORNING W/CONDITIONS IMPROVING TO VFR FOR KBGR AND KBHB. THE NORTHERN TERMINALS FROM KHUL TO KFVE WILL SEE MVFR HANG LONGER INTO THIS AFTERNOON. MVFR W/PERIODS OF IFR COULD BE SEEN LATER TONIGHT MAINLY ACROSS THE NORTHERN TAFS SITES W/SHOWERS AND LOW CIGS. SHORT TERM: MAINLY MVFR CONDITIONS ACROSS NRN AND CNTRL ME THROUGH THE PERIOD. OCNL PERIODS WERE CIGS WILL FALL IFR IN SHWRS. IFR CONDITIONS FOR BGR AND BHB THROUGH MUCH OF THE NEAR TERM PERIOD. IMPROVING CONDITIONS AFTER MID DAY MONDAY AS HIGHER PRESSURE BUILDS INTO THE AREA. && .MARINE... NEAR TERM: DROPPED THE SCA FOR HAZARDOUS SEAS AS WAVE HEIGHTS HAVE DROPPED BELOW 6 FT AND WILL CONTINUE TO SUBSIDE TODAY INTO TONIGHT. WINDS ARE AT 10 KTS ATTM AND THINKING HERE IS THAT THE WINDS WILL STAY LIGHT RIGHT INTO TONIGHT AT SPEEDS OF 10 KTS OR LESS. SHORT TERM: WINDS AND SEAS BELOW SCA THROUGH THE PERIOD. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT SHORT TERM...NORTON LONG TERM...NORTON AVIATION...HEWITT/NORTON MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
341 AM EDT FRI AUG 15 2014 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL REMAIN NORTHWEST OF MAINE THROUGH THE WEEKEND. AS A RESULT...UNSETTLED CONDITIONS WILL PERSIST ACROSS THE REGION RIGHT INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... UNSETTLED CONDITIONS THIS TERM W/ANOTHER ROUND OF SHOWERS EXPECTED. FOG WILL ALSO BE A CONCERN. THE 06Z SURFACE ANALYSIS SHOWED WEAK LOW PRES LIFTING ACROSS NEW BRUNSWICK W/THE OCCLUDED FRONT ACROSS NORTHERN MAINE. AREA OF SHOWERS ACROSS NEW BRUNSWICK MOVING NNW PER THE LATEST RADAR W/THE WESTERN EDGE JUST E OF THE MAINE BORDER. THE LATEST RAP AND HRRR 3KM DOING WELL W/THIS AREA AND THE PLACEMENT OF THE LOW AND FRONT. A BLEND OF THE THESE 2 MODELS SHOW THE WESTERN EDGE JUST SKIRTING THE MAINE-NEW BRUNSWICK BORDER THROUGH THIS MORNING AS THE BEST FORCING REMAINS WELL E AND SW OF THE REGION. OOZ UA AND SATELLITE WV IMAGERY SHOW CLOSED UPPER LOW SPINNING OVER QUEBEC W/SPOKES OF ENERGY ROTATING AROUND THE LOW. THE IMPULSE THAT IS FORECAST TO AFFECT OUR CWA WAS MOVING ACROSS NYS AND VT AND IS EXPECTED TO MOVE ACROSS THE REGION BY THIS AFTERNOON INTO THIS EVENING. SOME LLVL CONVERGENCE COMBINED W/SOME MID LEVEL SUPPORT WILL ALLOW FOR SHOWERS TO BREAK OUT MAINLY ACROSS THE NORTHERN AND CENTRAL AREAS. DECIDED TO GO W/CHANCE POPS(30-40%) FOR THIS AFTERNOON INTO TONIGHT BUT TRIMMED BACK THE QPF A BIT W/TOTALS THROUGH TONIGHT RUNNING LESS THAN 0.10". SOUNDINGS INDICATE SB/MUCAPES LESS THAN 150 JOULES TODAY INTO THE EVENING AND THEREFORE LEFT TSTMS OUT OF THE FORECAST. CLOUDS AND SHOWERS WILL HOLD DOWN TEMPERATURES W/READINGS WILL RUN INTO THE UPPER 60S ACROSS THE NORTH AND WEST WHILE CENTRAL AND DOWNEAST SHOULD SEE LOWER 70S. COOL FOR MID AUGUST. FOG HAS DEVELOPED THIS MORNING THANKS TO LIGHT WINDS/PARTIAL CLEARING AND A WET GROUND. THE FOG WAS THE MOST DENSE ACROSS THE COAST BUT PATCHY DENSE WILL BE NUISANCE THROUGH SUNRISE JUST ABOUT EVERYWHERE. DECIDED TO LEAVE FOG OUT NORTH OF THE DOWNEAST AND COASTAL AREAS TONIGHT DUE TO CLOUDS AND SHOWERS. ATTM, IT LOOKS AS THOUGH THE FOG ACROSS THE DOWNEAST AND THE COAST WILL BE PATCHY. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A UPPER LOW OVER NORTHERN QUEBEC AT THE START OF NEAR TERM PERIOD IS FORECAST TO DRIFT SLOWLY SOUTHEAST ACROSS NEW BRUNSWICK TO EASTERN NOVA SCOTIA BY THE END OF THE PERIOD. A NEW FRONTAL SYSTEM WILL MOVE FROM SRN MAINE TOWARDS THE EASTERN NOVA SCOTIA BY END OF THE PERIOD. UNSETTLE WEATHER WILL PERSIST ACROSS MAINE THROUGH THE PERIOD. LOADED USED HPC GRIDS FOR QPF...NAWAVE 4 FOR SEAS IN THE COASTAL WATERS...AND A BLEND OF NAM/GFS/GEM/ECMWF THROUGH THE PERIOD FOR ALL OTHER ELEMENTS. && .LONG TERM /MONDAY THROUGH THURSDAY/... AT THE START OF THE PERIOD AN UPPER LEVEL LOW WILL BE MOVING INTO THE WESTERN CANADIAN MARITIMES...HIGHER PRESSURE WILL BEGIN BUILDING INTO MAINE. THE RIDGE WILL SET ACROSS THE REGION AND REMAIN THROUGH THE END OF THE PERIOD. POSSIBLE SHOWERS ACROSS NRN MAINE TOWARDS THE END OF THE PERIOD AS LOWER PRESSURE BEGINS TO ERODE THE NORTHERN PORTIONS OF THE RIDGE. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR/IFR THIS MORNING W/CONDITIONS IMPROVING TO VFR FOR KBGR AND KBHB. THE NORTHERN TERMINALS FROM KHUL TO KFVE WILL SEE MVFR HANG LONGER INTO THIS AFTERNOON. MVFR W/PERIODS OF IFR COULD BE SEEN LATER TONIGHT MAINLY ACROSS THE NORTHERN TAFS SITES W/SHOWERS AND LOW CIGS. SHORT TERM: MAINLY MVFR CONDITIONS ACROSS NRN AND CNTRL ME THROUGH THE PERIOD. OCNL PERIODS WERE CIGS WILL FALL IFR IN SHWRS. IFR CONDITIONS FOR BGR AND BHB THROUGH MUCH OF THE NEAR TERM PERIOD. IMPROVING CONDITIONS AFTER MID DAY MONDAY AS HIGHER PRESSURE BUILDS INTO THE AREA. && .MARINE... NEAR TERM: DROPPED THE SCA FOR HAZARDOUS SEAS AS WAVE HEIGHTS HAVE DROPPED BELOW 6 FT AND WILL CONTINUE TO SUBSIDE TODAY INTO TONIGHT. WINDS ARE AT 10 KTS ATTM AND THINKING HERE IS THAT THE WINDS WILL STAY LIGHT RIGHT INTO TONIGHT AT SPEEDS OF 10 KTS OR LESS. SHORT TERM: WINDS AND SEAS BELOW SCA THROUGH THE PERIOD. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT SHORT TERM...NORTON LONG TERM...NORTON AVIATION...HEWITT/NORTON MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
129 AM EDT FRI AUG 15 2014 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL REMAIN NORTHWEST OF MAINE THROUGH THE WEEKEND. AS A RESULT...UNSETTLED CONDITIONS WILL PERSIST ACROSS THE REGION RIGHT INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 130 AM UPDATE: LARGE AREA OF SHOWERS HANGING ACROSS NEW BRUNSWICK W/SOME SCATTERED ACTIVITY ACROSS PORTIONS OF THE CENTRAL HIGHLANDS. LLVL CONVERGENCE RESIDES ACROSS NEW BRUNSWICK AND IN THE WESTERN AREAS AS EVIDENT OF THE LATEST SURFACE ANALYSIS. THE LATEST RUN OF THE HRRR 3KM WAS HANDLING THE PLACEMENTS OF RAINFALL WELL PER THE LATEST RADAR LOOP AS WELL AS THE RAP. LATEST UA COINCIDES W/THE SATELLITE WV LOOPS OF SHEARED VORTICITY RIDING N OVERNIGHT W/WEAK LIFT. THEREFORE, THINKING HERE IS THAT THE BULK OF THAT RAIN IN NEW BRUNSWICK WILL STAY E OF THE BORDER W/THE WESTERN EDGE GRACING AROOSTOOK COUNTY THROUGH EARLY MORNING. SOME PARTIAL CLEARING TAKING PLACE PER THE LATEST IR SATELLITE IMAGERY AND METARS. THIS HAS LED TO SOME FOG ESPECIALLY ACROSS DOWNEAST AND THE COAST. PREVIOUS SHIFTS HAVE FOG IN PLACE AND WILL KEEP IT AS IS THROUGH EARLY MORNING. FOR FRIDAY...AN UPPER LOW WILL SPIN ACROSS SOUTHERN QUEBEC THROUGH THE DAY. THIS WILL COMBINE WITH THE MOISTURE LINGERING FROM TODAY`S RAIN TO ALLOW SHOWERS TO DEVELOP, ESPECIALLY DURING THE AFTERNOON. NORTHWESTERN MAINE WILL HAVE THE BEST CHANCES FOR SEEING RAIN AS THEY WILL BE CLOSEST TO THE UPPER-LEVEL SUPPORT. HIGHS TOMORROW WILL BE ON THE COOL SIDE NORTH /MID 60S TO AROUND 70), WHILE SOUTHERN AREAS, WHICH WILL SEE SOME SUN ONCE THE FOG BURNS OFF, WILL BE A FEW DEGREES WARMER AWAY FROM THE COAST. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... UPPER LEVEL LOW PRESSURE WILL REMAIN NORTHWEST OF THE REGION FRIDAY NIGHT THROUGH SUNDAY...WHILE DISTURBANCES ROTATING AROUND THE LOW CROSS THE REGION. UNSETTLED CONDITIONS WILL PERSIST FRIDAY NIGHT THROUGH SUNDAY. THE BETTER CHANCES OF SHOWERS AND MOST EXTENSIVE CLOUD COVER FRIDAY NIGHT THROUGH SATURDAY NIGHT WILL OCCUR ACROSS NORTHERN AND CENTRAL PORTIONS OF THE FORECAST AREA. ACROSS DOWNEAST AREAS...EXPECT A SLIGHT CHANCE OF SHOWERS ALONG WITH PARTLY/MOSTLY CLOUDY SKIES FRIDAY NIGHT THROUGH SATURDAY NIGHT. SHOWER CHANCES WILL INCREASE ACROSS THE ENTIRE FORECAST AREA SUNDAY WITH A COLD FRONT STARTING TO MOVE EAST ACROSS THE REGION. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS SATURDAY/SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... UPPER LEVEL ENERGY MOVING OUT OF QUEBEC WILL KEEP REGION UNSETTLED THROUGH MONDAY. MODELS ARE NOT IN GREAT AGREEMENT ON THE EVOLUTION OF THE LOW AND UPPER LEVEL LOW THINKING THE BLEND APPROACH IS REASONABLE AT KEEPING THE BEST CHANCES OF PRECIP ACROSS NORTHERN MAINE WITH POPS LESSENING AS YOU GO SOUTHWEST FOR MONDAY. MONDAY NIGHT INTO TUESDAY EXPECT CHANCES OF PRECIP TO DROP OFF AS UPPER LEVEL RIDGE AND SURFACE HIGH BEGIN BUILDING EAST. HIGH PRESSURE WILL FINALLY TAKE OVER TUESDAY INTO EARLY WEDNESDAY WITH MOSTLY TO PARTLY SUNNY SKIES. THE MODELS DO HOWEVER INDICATE A LOW MOVING ACROSS THE MID ATLANTIC TUESDAY NIGHT. THE ECMWF WANTS TO BRING THIS LOW CLOSE TO THE REGION AS WE GO INTO LATER WEDNESDAY AND THE GFS/GFS ENSEMBLE KEEP THIS LOW SOUTH OF THE FA. DUE TO THE UNCERTAINTY IN THE MODELS WILL ONLY KEEP SLIGHT CHANCE PRECIP ACROSS THE REGION FOR WEDNESDAY INTO THURSDAY UNDER PARTLY CLOUDY SKIES. HIGH TEMPERATURES AT THE BEGINNING OF THE PERIOD WILL BE BELOW NORMAL AND THROUGH THE WEEK WILL COME UP TO NEAR TO A LITTLE ABOVE NORMAL. LOW TEMPERATURES ARE EXPECTED TO STAY CLOSE TO NORMAL THROUGH THE PERIOD. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... NEAR TERM: WIDESPREAD IFR EXPECTED TONIGHT INTO EARLY FRIDAY MORNING, WITH LIFR POSSIBLE, ESPECIALLY AT KHUL, KBGR, AND KBHB. THIS WILL BE DUE TO FOG AND LOW CEILINGS. CONDITIONS WILL GRADUALLY IMPROVE FRIDAY MORNING AS THE FOG BURNS OFF, ESPECIALLY AT KBHB AND KBGR, BUT EXPECT MVFR CEILINGS TO HANG ON ACROSS THE NORTH AS SHOWERS REDEVELOP BY AFTERNOON. SHORT TERM: OCCASIONAL MVFR CONDITIONS ARE POSSIBLE ACROSS THE REGION FRIDAY NIGHT THROUGH SATURDAY NIGHT...WITH THE BETTER CHANCES ACROSS NORTHERN AND CENTRAL AREAS. MORE EXTENSIVE MVFR CONDITIONS ARE EXPECTED ACROSS THE FORECAST AREA SUNDAY. OCCASIONAL MVFR CONDITIONS ARE POSSIBLE WITH ANY SHOWERS MONDAY. VFR CONDITIONS ARE EXPECTED MONDAY NIGHT AND TUESDAY. && .MARINE... NEAR TERM: 830 PM UPDATE...WV HTS DROPPED BLO 5 FT ACROSS THE INNER HARBOR/BAY MZ052...SO WE CANX THE SCA FOR HAZ SEAS THERE. WE XTNDED THE HAZ SEAS SCA OVR THE OUTER MZS TIL 08Z TO ALLOW MORE TM FOR WV HTS TO SUBSIDE THERE. OTHERWISE...NO OTHER CHGS WERE MADE. ORGNL DISC...A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN EFFECT FOR ALL OUR WATERS UNTIL 2 AM FRIDAY MORNING. ACROSS THE OUTER WATERS, 6-8 FOOT WAVES WILL SLOWLY SUBSIDE THROUGH THE EVENING. IN THE BAYS, WAVES ARE AT A MARGINAL 4-5 FEET, SO THE ADVISORY MAY BE ABLE TO BE CANCELLED EARLY IN THESE LOCATIONS. THE OTHER CONCERN IS THE POTENTIAL FOR DENSE FOG TONIGHT RESTRICTING VISIBILITY TO BELOW 1 SM. SHORT TERM: WINDS/SEAS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS FRIDAY NIGHT THROUGH THE WEEKEND. VISIBILITIES COULD BE REDUCED IN SHOWERS SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM EDT EARLY THIS MORNING FOR ANZ050-051. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
748 PM EDT SAT AUG 16 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 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 747 PM EDT SAT AUG 16 2014 LOW CLOUDS WILL BE A CHALLENGE THRU AT LEAST SUN MORNING...MAINLY AT KCMX/KSAW. WITH A GENERAL DOWNSLOPE EASTERLY FLOW AT KIWD...LOW CLOUDS ARE NOT EXPECTED...AND VFR CONDITIONS SHOULD PREVAIL. HOWEVER...IT`S NOT OUT OF THE QUESTION THAT SOME SHALLOW PATCHY FOG COULD DEVELOP OVERNIGHT. UPSTREAM TO THE N AND E OF KCMX/KSAW... PLENTY OF LOW CLOUDS ARE STILL PRESENT PER VIS SATELLITE IMAGERY. WHILE NE FLOW IS LESS FAVORABLE FOR LOW CLOUDS AT KCMX...PRESENCE OF CLOUDS UPSTREAM SUGGESTS MVFR CIGS SHOULD RETURN LATER THIS EVENING. WITH UPSLOPE N/NE WINDS AT KSAW...MVFR CIGS SHOULD PREVAIL THRU THE NIGHT. IMPROVEMENT TO VFR WILL OCCUR AT KCMX/KSAW LATE SUN MORNING/EARLY AFTN AS FLOW BECOMES MORE 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 MARQUETTE MI
359 PM EDT FRI AUG 15 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 351 PM EDT FRI AUG 15 2014 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS INTO THE SRN LAKES. TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300 MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90 KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF ANY SHOWERS EARLIER IN THE MORNING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 348 PM EDT FRI AUG 15 2014 MAIN FCST CONCERNS IN THE LONG RANGE WL FOCUS ON TEMPS/PSBL LO CLDS EARLY NEXT WEEK WITH NNE FLOW ON THE SRN FLANK OF DRY CNDN HI PRES FCST TO DOMINATE. HOW QUICKLY A CHC OF SHOWERS WL RETURN TO THE FCST IS THE CHALLENGE FOR THE MIDDLE OF NEXT WEEK. SAT NGT...UNDER CONFLUENT NW FLOW ALF BTWN UPR RDG IN THE PLAINS AND DEEP TROF IN QUEBEC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO DRIFT SLOWLY SEWD TOWARD NRN LK SUP BY 12Z SUN. ANY LINGERING CLDS EARLY OVER THE SCENTRAL ASSOCIATED WITH DEPARTING COLD FNT WL SHIFT TO THE S AS THE HI PRES BUILDS TOWARD THE CWA UNDER LARGER SCALE DNVA/DEEP LYR QVECTOR DVGC AND THE AIRMASS DRIES. IN FACT... GUIDANCE INDICATES PWAT WL SINK TO ARND 0.5 INCH BY 12Z SUN...ABOUT 50 PCT OF NORMAL. THE MAJOR CONCERN IS THE POTENTIAL FOR SOME LO CLDS TO DVLP...MAINLY IN THOSE AREAS OVER THE NCNTRL IMPACTED BY UPSLOPE NNE WIND COMPONENT ON THE SRN FLANK OF THE APRCHG HI PRES. IN FACT...THE 12Z NAM/REGIONAL CNDN/LOCAL WRF ARW FCST SDNGS SHOW A SHALLOW...MOIST INFUSION OF COOLER AIR BLO SHARP SUBSIDENCE INVRN BASED NEAR H9 ASSOCIATED WITH THE LARGER SCALE SUBSIDENCE/DRYING. THESE FCSTS ARE BACKED UP BY SOME FAIRLY EXTENSIVE LO CLD COVER NOW PRESENT OVER FAR NW ONTARIO ASSOCIATED WITH SHALLOW MOIST LYR DEPICTED ON THE 12Z CHURCHILL MANITOBA RAOB. WL THUS INTRODUCE MORE CLDS INTO THE FCST...MAINLY OVER THE NCENTRAL. THESE CLDS AND EXPECTED STEADY NNE WIND WL LIMIT THE DIURNAL TEMP FALL A BIT ESPECIALLY NEAR LK SUP OVER THE E HALF WHERE THE PRES GRADIENT IS FCST TO BE A BIT TIGHTER. EXPECT THE LOWEST MIN TEMPS IN THE 40S OVER THE INTERIOR W...CLOSER TO THE RDG AXIS EXTENDING FM THE HI CENTER S TOWARD THE UPR MIDWEST AND WHERE WINDS WL BE LIGHTER AND DOWNSLOPE WIND COMPONENT SHOULD LIMIT THE POTENTIAL FOR MORE EXTENSIVE LO CLD. SUN THRU MON...AS UPR RDG AXIS BUILDS INTO THE GREAT LKS FM THE W FOLLOWING A SLOWLY EXITING QUEBEC TROF...SFC HI PRES IS FCST TO DRIFT SLOWLY E AND INTO WRN QUEBEC BY MON AFTN. AM LO CLDS MAINLY OVER THE NCENTRAL ON SUN MRNG SHOULD MIX OUT DURING THE AFTN WITH DAYTIME HEATING AND THE ARRIVAL OF DRIER AIR. OTRW...THE WX OVER UPR MI SHOULD REMAIN UNEVENTFUL WITH RDG AXIS EXTENDING WWD FM THE HI CENTER INTO THE UPR LKS AND RELATIVELY DRY AIRMASS LINGERING. BOTH SUN AND MON SHOULD FEATURE PLEASANT MAX TEMPS IN THE 70S AWAY FM LK MODERATION AS H85 TEMPS ARE FCST TO TOP OUT BTWN 10-12C AND SUN AND 11-13C ON MON. MIN TEMPS ON SUN NGT WL DIP INTO THE 40S OVER THE INTERIOR UNDER MOCLR SKIES/LIGHT WINDS DESPITE A SLOW INCRS IN PWAT AOA 0.75 INCH. EXTENDED...REMNANT OF CUTOFF UPR LO NOW MOVING EWD THRU THE PAC NW IS FCST TO DRIFT SLOWLY E AND INTO THE UPR LKS ON TUE-THU NEXT WEEK AT THE SAME TIME LARGER SCALE UPR RDG WL BE BUILDING OVER THE UPR LKS DOWNSTREAM OF DEEPENING TROF OVER WRN CANADA/THE NW CONUS. FCST WL INCLUDE SOME POPS AS THE SHRTWV/DEEPER MSTR INFLUENCE THE AREA... BUT SLOWLY RISING H5 UNDER THE EXPANDING MEAN RDG SHOULD TEND TO LIMIT THE SHOWER COVERAGE AND POPS TO THE CHC RANGE. WITH FCST H85 TEMPS NOT FAR FM 13-15C AND SOME CLDS...TEMPS SHOULD BE NOT FAR FM THE MID/LATE AUG NORM. AS THE SHRTWV/DEEPER MSTR SLOWLY LIFT TO THE NE AND H85 TEMPS WARM INTO THE 17-20C RANGE BY NEXT FRI UNDER THE SLOWLY BLDG UPR RDG...EXPECT A RETURN OF ABV NORMAL TEMPS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 143 PM EDT FRI AUG 15 2014 VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING...AS DRY HIGH PRESSURE AREA BUILDS TO THE SOUTH...AND INCREASED MOISTURE BEGINS TO MOVE IN. A DISTURBANCE AND COLD FRONT MOVING SE THROUGH THE NRN LAKES WILL BRING SCT SHOWERS AND POSSIBLY A THUNDERSTORMS TO CMX/SAW LATE TONIGHT INTO EARLY SAT. BEHIND THE COLD FRONT...NRLY FLOW WITH COMBINED WITH ABUNDANT LOW LEVEL MOISTURE IS LIKELY TO BRING IFR CIGS TO CMX/SAW SAT MORNING AND MVFR CIGS TO IWD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 348 PM EDT FRI AUG 15 2014 EXPECT WINDS UNDER 20 KTS THRU NEXT WED 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...JLB LONG TERM...KC AVIATION...JLB MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
357 PM CDT FRI AUG 15 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 357 PM CDT FRI AUG 15 2014 RAIN HAS PUSHED WELL TO THE SOUTH INTO IOWA THIS AFTERNOON FROM SOUTHWESTERN MN THIS MORNING. CONSIDERABLE CLOUDINESS CONTINUES... PARTICULARLY OVER WRN MN WHERE LOWER CLOUDS ARE BEING OBSERVED IN RICHER LOW LEVEL MOISTURE...WITH MORE FAIR WX CU ACROSS ERN MN AND WRN WI. DEW POINTS HAVE RISEN A GOOD 5 TO 15 DEGREES ACROSS THE CWA SINCE YESTERDAY AFTERNOON WITH WAA EXPECTED TO CONTINUE THROUGH SATURDAY. MODELS ARE A BIT AT ODDS WITH RESPECT TO FOG AND LOW STRATUS TONIGHT WITH THE HI-RES MODELS INCLUDING THE HRRR...HOPWRF...AND RAP NOT SHOWING TOO MUCH...WHILE FORECAST SOUNDINGS OF THE NAM AND GFS AND THEIR MOS PRODUCTS INDICATING MUCH MORE IN THE WAY OF RICH BOUNDARY LAYER MOISTURE. GIVEN THE RECENT DRY SPELL...I AM HESITANT TO BUY INTO WIDESPREAD DENSE FOG AND AM THINKING MORE LOW CLOUD FORMATION...ESPECIALLY IF 15-20 KT WINDS AROUND 1KFT VERIFIES. DID ADD AREAS OF FOG INTO THE GRIDS...BUT AT THIS POINT IT SHOULD NOT BE ANYTHING TOO SIGNIFICANT OUTSIDE OF AVIATION INTERESTS. TONIGHT AND MOST OF SATURDAY IS LOOKING DRY. LITTLE IN THE WAY OF FORCING WILL PRECLUDE DEVELOPMENT UNTIL SATURDAY AFTERNOON IN CENTRAL MN AND NWRN WI WHEN A WEAK COOL FRONT ADVANCES SOUTH FROM NORTHERN MINNESOTA AND LAKE SUPERIOR. THERE WILL BE A SECONDARY AREA OF FORCING ACROSS SOUTHWESTERN MN WHERE A WEAK VORTICITY MAX PUSHES IN DURING THE LATE AFTERNOON. HOWEVER...MID LEVEL RIDGING WILL ALSO BE IN PLACE WHICH SHOULD LIMIT THE OVERALL COVERAGE TO SLIGHT CHC TO LOW CHC RANGE INTO EVENING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 357 PM CDT FRI AUG 15 2014 FOR THE LONG TERM...BEST CHANCE FOR PRECIP STILL LOOKS TO COME MONDAY INTO TUESDAY...WHERE ONE WILL CONTINUE TO FIND LIKELY POPS. AFTER THAT...MODEL DISAGREEMENT STARTS TO INCREASE APPRECIABLY...THOUGH WE ARE STILL SEEING THE IDEA OF A TROUGH SETTING UP ACROSS THE NORTHERN ROCKIES...THERE ARE JUST SIGNIFICANT TIMING DIFFERENCES AS TO WHEN ENERGY FROM SAID TROUGH WORKS ACROSS THE NORTHERN PLAINS. WE WILL BE STARTING OFF THIS PERIOD WITH HIGH PRESSURE AGAIN BUILDING SOUTH ACROSS THE GREAT LAKES FROM WESTERN ONTARIO. THIS WILL PUSH A WEAK COLD INTO SW MN SATURDAY NIGHT...HELPING CONFINE THE INSTABILITY THROUGH SUNDAY INTO SW MN AS WELL...AS DRIER AIR WORKS IN FROM THE NORTHEAST. HAVE MAINTAINED SOME 20 POPS OUT IN SW MN FOR AREAS THAT ARE EXPECTED TO BE NEAR THE BOUNDARY. HAVE GONE NO HIGHER THAN THAT WITH POPS AS OUTSIDE OF THAT WEAK SFC BOUNDARY...THE FORCING IS NIL AS AN H5 ANTICYCLONE WILL BE DRIFTING OVER MN...WITH NO LLJ SUPPORT TO SPEAK OF EITHER WITH H85 RIDGING MOVING THROUGH AS WELL. FOR MONDAY...PRECIP CHANCES WILL BE ON THE INCREASE AS THE UPPER LOW CURRENTLY SPINNING ACROSS WASHINGTON WORKS THROUGH THE RIDGE AND COMES DIVING ACROSS MN MONDAY AND ACROSS WI TUESDAY. THIS HAS BEEN A FAIRLY STABLE SIGNAL IN THE MODELS THE PAST FEW DAYS...SO CONTINUED TO RUN WITH LIKELY POPS...THOUGH SLOWED THEIR EWRD PROGRESSION ACROSS THE AREA SUNDAY NIGHT INTO MONDAY...AS ONCE AGAIN WE WILL HAVE VERY DRY HIGH PRESSURE OVER THE GREAT LAKES HELPING TO SLOW THE EWRD PROGRESSION OF MOISTURE/PRECIP WITH THIS SYSTEM. STILL LOOKS GOOD FOR A WIDESPREAD QUARTER TO ONE INCH WITH THIS SYSTEM...BUT DOES NOT LOOK LIKE HEAVY PRECIP WILL BE MUCH OF A THREAT...AS MOISTURE TRANSPORT DOES NOT LOOK TO GET CARRIED AWAY...WITH THE LLJ ONLY TOPPING OUT AROUND 20 KTS...AND THE PW PLUME ASSOCIATED WITH THIS PRECIP WILL ONLY BE AROUND 1.5 INCHES. WE JUST LOOK TO HAVE GOOD UPPER DIFFLUENCE AND FORCING WITH THE H5 WAVE DROPPING ACROSS THE AREA. SEVERE THREAT LOOKS MINIMAL AS WELL AS BOTH THERMODYNAMIC AND KINEMATIC FIELDS LOOK WEAK...JUST LOOKS LIKE SOME MUCH NEEDED LIGHT-MODERATE RAIN AT THIS POINT. FROM TUESDAY AND BEYOND...MODEL DISCREPANCIES INCREASE QUITE A BIT WITH THE WAVE AS IT MOVES FROM MN TOWARD THE GREAT LAKES. THE GEM/GFS MAINTAIN A DEEPER/STRONGER UPPER WAVE ACROSS MN/WI...WHILE THE ECMWF ALLOWS IT TO GET ABSORBED INTO THE MAIN BELT OF WESTERLIES. THIS DIFFERENCE IN TURN INFLUENCES HOW THE MODELS BEGIN TO BRING THE DEVELOPING TROUGH IN THE NRN ROCKIES OUT INTO THE PLAINS. THE GEM/GFS SOLUTION KEEPS THE UPPER LOW OVER THE GREAT LAKES LONGER...WHICH IN TURN KEEPS ENERGY WITH THE WRN TROUGH HELD UP OUT WEST UNTIL THE WEEKEND. THE ECMWF ALLOWS FOR A MUCH MORE PROGRESSIVE PATTERN WITH RESPECT TO THE TROUGH...BRINGING PIECES OF THE TROUGH ACROSS THE UPPER MS VALLEY ON THURSDAY AND AGAIN OVER THE WEEKEND. THE GFS/GEM SOLUTION WOULD KEEP ANY ENERGY FROM THE WRN TROUGH GETTING HERE UNTIL THE WEEKEND...WITH WEDNESDAY THROUGH FRIDAY OF NEXT WEEK BEING MAINLY DRY AS WE STAY UNDER MORE OF THE INFLUENCE OF AN UPPER RIDGE...AS THE INFLUENCE OF THE UPPER THROUGH REMAINS TO THE NORTHWEST. GIVEN THE SPREAD IN MODELS...KEPT CLOSE TO GFS/ECMWF BLEND FOR POPS...WHICH MEANS POPS TUESDAY ARE MAINLY TO THE EAST /CLOSER TO THE UPPER LOW/...WEDNESDAY IS MAINLY DRY...WHILE THU/FRI SEES THE RETURN OF 20-30 POPS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 117 PM CDT FRI AUG 15 2014 SOME MVFR CIGS ARE PRESENT AT TAF ISSUANCE TIME ACROSS WRN MN...CLOSEST TO WHERE RAIN FELL EARLIER THIS MORNING. THESE CIGS HAVE BEEN RISING AS THEY PUSH OVER WARMER LOCATIONS AS EXPECTED SO NOT ANTICIPATING TOO MANY ISSUES AT RWF AND AXN TODAY. LOW LEVEL MOISTURE WILL INCREASE TONIGHT WHICH WILL LEAD TO AREAS OF FOG AND IFR/LIFR STRATUS POTENTIAL. WINDS WILL BE LIGHT...BUT THE GROUND HAS BEEN QUITE DRY AS OF LATE SO LEANING MORE TOWARD THE STRATUS SIDE OF THINGS. STILL CANNOT RULE OUT BRIEF INSTANCES OF DENSE FOG AT ANY OF THE TAF SITES EXCEPT MSP LATE TONIGHT AND SATURDAY MORNING. KMSP...VFR TODAY WITH DETERIORATING CONDITIONS LIKELY LATE TONIGHT AND SATURDAY MORNING. AS FOG DEVELOPS IN THE OUTLYING AREAS TONIGHT...IT WILL LIFT INTO STRATUS SATURDAY MORNING SO FAIRLY CONFIDENT IN IFR CIGS FOR A TIME. VFR CONDITIONS RETURN FOR THE LATE MORNING AND AFTERNOON. /OUTLOOK FOR KMSP/ SUN...VFR. WIND E 5-10 KTS. MON...VFR/MVFR WITH TSRA LIKELY...MAINLY LATE. WINDS S 5-10 KTS. TUE...VFR WITH TSRA POSSIBLE EARLY. WIND NW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...BORGHOFF LONG TERM...MPG AVIATION...BORGHOFF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
949 PM CDT Sat Aug 16 2014 .UPDATE: Issued at 942 PM CDT Sat Aug 16 2014 The lastest 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 00z TAFs through 00z Sunday Evening) Issued at 604 PM CDT Sat Aug 16 2014 Specifics for KUIN, KCOU: The primary concerns during the first 6 hours of the TAF period are thunderstorms followed by the onset of MVFR/IFR cigs. Thunderstorms were ongoing at KUIN at TAF issuance and may redevelop near KCOU over the next 2-3 hours as a cold front moves across the area. A prolonged period of IFR ceilings is expected overnight and tomorrow. Some improvement to to MVFR is possible during the mid to late afternoon depending on how quickly a low pressure system moves away from the area. Specifics for KSTL, KSUS, KCPS: The primary concerns during the first 6 hours of the TAF period are thunderstorms followed by the onset of MVFR/IFR cigs. Thunderstorms have developed west of the St. Louis metro area terminals and are expected to reach KSUS/KSTL/KCPS between 00-03z. Conditions will briefly deteriorate when thunderstorms pass overhead followed by a prolonged period of IFR ceilings lasting overnight and into tomorrow. Some improvement to MVFR is possibly by late afternoon depending on how quickly a low pressure system moves away from the area. Kanofsky && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
356 PM CDT Fri Aug 15 2014 .SHORT TERM: (Through Sunday Afternoon) Issued at 355 PM CDT Fri Aug 15 2014 An initial round of showers was located over UIN-COU and has been steadily heading east with no models handling this well at all. This rain was initially fueled by a low level jet and WAA along and just north of an effectively stationary frontal boundary stretching from northwest MO thru the STL metro area and into far southern IL. But with little downstream to slow it down, it has not diminished much as it has pushed east. We expect this to move into STL metro eventually toward sunset as scattered SHRA before finally dwindling. A more organized system lurks further to the northwest over eastern Nebraska, and with the prevailing northwest flow over our region, will move east-southeast towards northeast MO by Saturday morning and thru southwest IL later on Saturday night and Sunday morning, pulling away Sunday afternoon. There have been some discrepancies between the models on exactly how fast and where to move this system with an early merger with another upper level disturbance in the works this evening, but the latest runs seem to confirm the slow nature of it and with a track that makes logical sense. This system will also carry with it very moist air thru the column, with PWs in excess of two inches, which is higher than two standard deviations above the mean for mid-August. Have been generous with PoPs given the available moisture and slow moving nature of the system, with likelys every period thru Sunday, but in the end, probably not high enough and categorical range will be needed at some point, just a matter of where. Localized heavy rainfall will be the main threat thru the weekend, especially if nocturnal rainfall can get going, but not to the point of where feel a Flash Flood Watch is needed. Severe threats will be marginal each day, peaking with the max heating in the afternoon, and likely on the southeast flank of the best lo level focus where the better instability will be. On Saturday, probably south of UIN, thru COU with STL metro on the southeast edge. On Sunday, southeast of STL metro, perhaps outside of the CWA. TES .LONG TERM: (Monday through Next Friday) Issued at 355 PM CDT Fri Aug 15 2014 The rather moist atmosphere will remain in place on Monday, with another weak upper level system possible. Models are resolving this poorly but will not take much to get something going either, so have maintained a low PoP. More of the same with weak disturbances possible in the NW flow thru the middle of next week and so have no real reason to drop the chance mention of rain. Max temps each day will be seasonably warm but held in check somewhat by rain threat. By late next week, there is a trend to go more zonal with the flow and build the upper ridge--a more typical summertime pattern we have seen very little of this year. Trended towards dry and above average on temps, which places daytime maxes in the 90s. If the humidity holds, could see potentially dangerous heat and humidity for next weekend. TES && .AVIATION: (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1109 AM CDT Fri Aug 15 2014 Bit of a tricky forecast this period, and as usual models not in total agreement in a northwest flow situation. Main issue is what will happen with the two short waves. Most models basically want to combine them while the GFS makes a case to keep them separate. Models were slow with the existing warm air advection rain over northern MO. The HRRR is the best right now with the existing rain, and it develops another mass of rain over NW MO this evening and moves it east overnight. Given lack of confidence in other model solution will trend the forecast toward the HRRR. Specifics for KSTL: Appears existing TSRA/SHRA will stay north of terminal so expect to stay dry with mid cloud overcast today into this evening. Per the HRRR, rain could move into the area at 06z or shortly after. Will move up the existing forecast VCTS 1 hour to 08z. A prevailing looks possible by 12z, but will leave it out for now. Hopefully the next model runs trend toward a more universal decision. Cold front does not drag across the terminal until Sunday morning, with the GFS a bit faster than the NAM. Would expect covection to fire up again Sat afternoon into the evening so another VCTS will be needed after 18z Sat. JPK && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
350 PM CDT Fri Aug 15 2014 .SHORT TERM: (Through Late Tonight) Issued at 350 PM CDT Fri Aug 15 2014 An initial round of showers was located over UIN-COU and has been steadily heading east with no models handling this well at all. This rain was initially fueled by a low level jet and WAA along and just north of an effectively stationary frontal boundary stretching from northwest MO thru the STL metro area and into far southern IL. But with little downstream to slow it down, it has not diminished much as it has pushed east. We expect this to move into STL metro eventually toward sunset as scattered SHRA before finally dwindling. A more organized system lurks further to the northwest over eastern Nebraska, and with the prevailing northwest flow over our region, will move east-southeast towards northeast MO by Saturday morning and thru southwest IL later on Saturday night and Sunday morning, pulling away Sunday afternoon. There have been some discrepancies between the models on exactly how fast and where to move this system with an early merger with another upper level disturbance in the works this evening, but the latest runs seem to confirm the slow nature of it and with a track that makes logical sense. This system will also carry with it very moist air thru the column, with PWs in excess of two inches, which is higher than two standard deviations above the mean for mid-August. Have been generous with PoPs given the available moisture and slow moving nature of the system, with likelys every period thru Sunday, but in the end, probably not high enough and categorical range will be needed at some point, just a matter of where. Localized heavy rainfall will be the main threat thru the weekend, especially if nocturnal rainfall can get going, but not to the point of where feel a Flash Flood Watch is needed. Severe threats will be marginal each day, peaking with the max heating in the afternoon, and likely on the southeast flank of the best lo level focus where the better instability will be. On Saturday, probably south of UIN, thru COU with STL metro on the southeast edge. On Sunday, southeast of STL metro, perhaps outside of the CWA. TES .LONG TERM: (Saturday through Next Friday) Issued at 350 PM CDT Fri Aug 15 2014 The rather moist atmosphere will remain in place on Monday, with another weak upper level system possible. Models are resolving this poorly but will not take much to get something going either, so have maintained a low PoP. More of the same with weak disturbances possible in the NW flow thru the middle of next week and so have no real reason to drop the chance mention of rain. Max temps each day will be seasonably warm but held in check somewhat by rain threat. By late next week, there is a trend to go more zonal with the flow and build the upper ridge--a more typical summertime pattern we have seen very little of this year. Trended towards dry and above average on temps, which places daytime maxes in the 90s. If the humidity holds, could see potentially dangerous heat and humidity for next weekend. TES && .AVIATION: (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1109 AM CDT Fri Aug 15 2014 Bit of a tricky forecast this period, and as usual models not in total agreement in a northwest flow situation. Main issue is what will happen with the two short waves. Most models basically want to combine them while the GFS makes a case to keep them separate. Models were slow with the existing warm air advection rain over northern MO. The HRRR is the best right now with the existing rain, and it develops another mass of rain over NW MO this evening and moves it east overnight. Given lack of confidence in other model solution will trend the forecast toward the HRRR. Specifics for KSTL: Appears existing TSRA/SHRA will stay north of terminal so expect to stay dry with mid cloud overcast today into this evening. Per the HRRR, rain could move into the area at 06z or shortly after. Will move up the existing forecast VCTS 1 hour to 08z. A prevailing looks possible by 12z, but will leave it out for now. Hopefully the next model runs trend toward a more universal decision. Cold front does not drag across the terminal until Sunday morning, with the GFS a bit faster than the NAM. Would expect covection to fire up again Sat afternoon into the evening so another VCTS will be needed after 18z Sat. JPK && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1142 AM CDT Fri Aug 15 2014 .SHORT TERM: (Through Tonight) Issued at 245 AM CDT Fri Aug 15 2014 Focus thru this period will be precip chances. TSRA have developed on the nose of the LLJ over wrn IA and nwrn MO. These storms may move sewd thru the morning, but believe they will struggle to reach the CWA. Believe isod to sct storms will be possible this afternoon as an approaching s/w reaches the region. Chances increase tonight as the LLJ ahead of the low approaches the region. As for temps, have trended twd the warmer guidance thru the period. While ample clouds shud linger thru today, the approaching thermal ridge shud allow temps to climb despite the cloud cover. Cloud cover tonight shud also help keep temps warm. Tilly .LONG TERM: (Saturday through Thursday) Issued at 334 AM CDT Fri Aug 15 2014 Storms shud be ongoing across nrn portions of the CWA Sat morning. These storms shud dissipate during the morning allowing for heating and redevelopment during the afternoon, persisting into the evening. Differences among mdls reduce confidence somewhat. However, with fropa expected on Sat, storms shud be possible across much of the region again mainly during the afternoon into overnight. Mdls suggest a sfc boundary may linger across portions of the area on Sun. Have kept chance PoPs across much of the area due to timing differences for precip moving out of the area on Sat night as well as the boundary which may provide a focus for additional storms. For Mon and beyond, mdls suggest upper level ridge building over the region with height rises persisting thru the end of the period. While the GFS suggests much more precip compared to the ECMWF, have kept low chance PoPs going due to the uncertainty. Have trended twd a warming trend thru the end of the period with the height rises. Tilly && .AVIATION: (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1109 AM CDT Fri Aug 15 2014 Bit of a tricky forecast this period, and as usual models not in total agreement in a northwest flow situation. Main issue is what will happen with the two short waves. Most models basically want to combine them while the GFS makes a case to keep them separate. Models were slow with the existing warm air advection rain over northern MO. The HRRR is the best right now with the existing rain, and it develops another mass of rain over NW MO this evening and moves it east overnight. Given lack of confidence in other model solution will trend the forecast toward the HRRR. Specifics for KSTL: Appears existing TSRA/SHRA will stay north of terminal so expect to stay dry with mid cloud overcast today into this evening. Per the HRRR, rain could move into the area at 06z or shortly after. Will move up the existing forecast VCTS 1 hour to 08z. A prevailing looks possible by 12z, but will leave it out for now. Hopefully the next model runs trend toward a more universal decision. Cold front does not drag across the terminal until Sunday morning, with the GFS a bit faster than the NAM. Would expect covection to fire up again Sat afternoon into the evening so another VCTS will be needed after 18z Sat. JPK && .PRELIMINARY POINT TEMPS/POPS: Saint Louis 89 72 89 74 / 20 30 50 60 Quincy 84 68 85 68 / 30 60 60 70 Columbia 89 69 90 70 / 20 50 50 60 Jefferson City 90 70 90 71 / 20 40 40 50 Salem 83 66 85 69 / 10 10 40 60 Farmington 86 68 86 69 / 20 20 30 40 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1010 PM EDT SAT AUG 16 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 /MONDAY THROUGH FRIDAY/... AS OF 325 PM SATURDAY... THE UPPER AIR PATTERN AT THE BEGINNING OF THE LONG TERM FEATURES A WEAKENING UPPER LEVEL TROUGH MOVING ACROSS THE OH/TN VALLEYS ON MONDAY THAT MOVES EAST AND OFF THE COAST BY LATE TUESDAY. A WEAK SURFACE LOW DEVELOPS AND MOVES ACROSS NORTHERN WV AND VA. NWP GUIDANCE IS CONSISTENT IN DEPICTING DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF 1.8 TO 2.0 INCHES ON MONDAY AND MONDAY NIGHT ACROSS CENTRAL NC WITH THE DEEP MOISTURE AXIS SLIPPING EAST TOWARD THE COAST BUT INCREASING ON TUESDAY. AFTERNOON MLCAPE VALUES CLIMB TO 1000-2000 J/KG MONDAY AFTERNOON AND ARE FAIRLY SIMILAR TUESDAY AFTERNOON. WITH MODERATE INSTABILITY AND DECENT FORCING EXPECT DECENT CONVECTIVE COVERAGE ON MONDAY THAT WILL PERSIST INTO MONDAY NIGHT WITH POPS IN THE 30-40% RANGE. SIMILAR BUT PERHAPS SLIGHTLY DECREASED POPS ARE EXPECTED ON TUESDAY WITH A FOCUS ACROSS THE EASTERN CAROLINAS. GUIDANCE FOR MAX TEMPS ON MONDAY AND TUESDAY HAVE TRENDED DOWNWARD FOR THE PAST COUPLE OF DAYS. WITH A FAIR AMOUNT OF CLOUDINESS EXPECT HIGHS IN THE UPPER 80S TO LOWER 90S WITH LOWS AROUND 70. THE REST OF THE LONG TERM BECOMES A LITTLE NEBULOUS AS THE UPPER FLOW PATTERN TRANSITIONS FROM A MORE WESTERLY FLOW TO A NORTHWESTERLY FLOW. DEEP LAYER MOISTURE DECREASES ON WEDNESDAY AND THEN RAMPS BACK FOR THURSDAY AND ESPECIALLY FRIDAY. BEST CHANCE OF PRECIPITATION APPEARS TO BE AT THE END OF THE PERIOD ON FRIDAY WHEN GUIDANCE APPEARS TO BE PICKING UP ON A MORE SUBSTANTIV WAVE IN THE NORTHWEST FLOW. FORECAST RESEMBLES CLIMATOLOGY GIVEN THE UNCERTAINTY WITH SLIGHT TO LOW CHANCE POPS OF MAINLY DIURNALLY FORECAST CONVECTION. HIGHS SHOULD RANGE IN THE LOWER 90S ON WEDNESDAY AND THURSDAY AND PERHAPS A COUPLE OF DEGREES COOLER ON FRIDAY. MORNING LOWS WILL RANGE IN THE UPPER 60S TO LOWER 70S. -BLAES && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 755 PM SATURDAY... 24-HR TAF PERIOD: CONVECTION WILL QUICKLY DISSIPATE AFTER SUNSET. WEAK SHORTWAVE DISTURBANCES EMBEDDED IN THE NW FLOW ALOFT WILL RESULT IN A OCCASIONAL BROKEN MID AND HIGH LEVEL CLOUD COVER OVERNIGHT WHICH SHOULD HELP TO DETER WIDESPREAD FOG DEVELOPMENT. HOWEVER...THERE IS STILL THE POTENTIAL FOR PATCHY ACROSS THE SANDHILLS/SOUTHERN COASTAL PLAIN WHERE THEY SAW HEAVY RAINFALL EARLIER THIS EVENING. WILL INCLUDE SOME SUB-VFR RESTRICTIONS AT ONLY KFAY AND KRWI AT THIS TIME. OTHERWISE...PREDOMINATELY VFR CONDITIONS ARE EXPECTED ON SUNDAY WITH ISOLATED STORMS POSSIBLE DURING THE AFTERNOON. LOOKING AHEAD: CHANCES FOR CONVECTION WILL INCREASE ABOVE CLIMATOLOGY BY EARLY TO MID NEXT WEEK (MON-WED)...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS...IN ASSOCIATION WITH AN ACTIVE WNW/NW FLOW ALOFT. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY...ESPECIALLY IN LOCATIONS RECENTLY AFFECTED BY CONVECTION. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BSD SHORT TERM...VINCENT LONG TERM...BLAES AVIATION...CBL/VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
556 PM CDT FRI AUG 15 2014 .UPDATE... ISSUED AT 556 PM CDT FRI AUG 15 2014 THE LATEST MODEL GUIDANCE CONTINUES TO PROG THE HEAVY RAIN POTENTIAL CONTINUING OVER SOUTHWESTERN NORTH DAKOTA TONIGHT. MOST MODELS ARE A LITTLE TOO FAR SOUTH WITH THE ONGOING ACTIVITY...WITH THE 12Z GEM ACTUALLY DOING A PRETTY GOOD JOB PAINTING THE HIGHEST QPF WHERE THE CURRENT CONVECTION IS LOCATED. FOR THE UPDATE...ADJUSTED POPS UPWARDS BASED ON CURRENT RADAR OBS AND EXTRAPOLATED THE HIGHER POPS SOUTHEASTWARD THROUGH THE OVERNIGHT HOURS...BASED ON THE 12Z GEM SOLUTION. WILL KEEP THE CURRENT FLASH FLOOD WATCH AS IS FOR THIS UPDATE. ALSO EXTENDED THE FLOOD ADVISORY FOR BILLINGS...SOUTHWESTERN MCKENZIE...AND GOLDEN VALLEY COUNTIES UNTIL 530 AM CDT. THE LATEST RAINFALL REPORT FROM BEACH IS 4.6 INCHES...AND IT IS STILL RAINING. OVERLAND FLOODING CONTINUES TO BE AN ISSUE WITH SOME COUNTY ROADS UNDER WATER. THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 549 PM CDT FRI AUG 15 2014 HEAVY RAINFALL AND ASSOCIATED FLASH FLOODING WILL HIGHLIGHT THE SHORT TERM FORECAST. EXTENDED THE FLASH FLOOD WATCH THROUGH 12 UTC SATURDAY ACROSS THE SOUTHWEST. THE 12 UTC WRF-ARW/NMM...INCOMING 18 UTC NAM AND 16-17 UTC HRRR ITERATIONS CONTINUE TO FOCUS RAIN SHOWERS AND THUNDERSTORMS WITH PROLONGED MODERATE TO HEAVY RAINFALL ACROSS THE SOUTHWEST AND FAR SOUTH CENTRAL LATE THIS AFTERNOON AND INTO THE EARLY EVENING IN ASSOCIATION WITH THE UPPER LEVEL LOW EVIDENT ON WATER VAPOR ACROSS THE SOUTHWEST. THESE SOLUTIONS WANE CONVECTION A BIT AFTER SUNSET...THEN REDEVELOP THUNDERSTORMS ACROSS THE WEST REINVIGORATED BY INCREASING UPPER LEVEL DIFFLUENCE AND IMPULSES EJECTING OUT OF THE PACIFIC NORTHWEST CLOSED LOW. THIS IS IN AGREEMENT WITH NESDIS SATELLITE PRECIPITATION ESTIMATES AND HIGHLIGHTS FOR HEAVY RAINFALL TONIGHT. GIVEN THIS REGENERATION OF SLOW MOVING STORMS LATE TONIGHT OVER ALREADY SATURATED AREAS WITH PWATS NEAR 1.75 INCHES...THE EXTENSION OF THE WATCH IS WARRANTIED. THE 12 UTC WRF-ARW/NMM DO HIGHLIGHT SIOUX AND EMMONS COUNTIES LATE TONIGHT AS WELL FOR HEAVY RAIN...AND THIS WILL HAVE TO BE MONITORED. ADDITIONAL SCATTERED THUNDERSTORMS WITH HEAVY RAIN WILL CONTINUE ACROSS MUCH OF THE AREA SATURDAY AS THE PACIFIC NORTHWEST UPPER LEVEL LOW BEGINS TO PROPAGATE INTO THE NORTHERN PLAINS. WILL ALLOW FURTHER SHIFTS TO EVALUATE IF A FLASH FLOOD WATCH IS NEEDED. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 549 PM CDT FRI AUG 15 2014 THE MAIN FORECAST ISSUE IN THE EXTENDED PERIOD WILL CONTINUE TO BE THE THREAT OF HEAVY RAINFALL THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. DETERMINISTIC MODELS ARE IN REASONABLE AGREEMENT IN BRINGING AN UPPER LEVEL LOW CURRENTLY OVER EASTERN WASHINGTON...EAST ALONG THE INTERNATIONAL BORDER...TO THE EASTERN DAKOTAS BY MONDAY AFTERNOON. ALTHOUGH THE THREAT OF SEVERE WEATHER WILL BE LOW. WE WILL STILL NEED TO MONITOR THE THREAT OF HEAVY RAINFALL... PARTICULARLY IN THE SUNDAY NIGHT INTO EARLY MONDAY PERIOD. PERHAPS A BRIEF DRY PERIOD TUESDAY INTO EARLY WEDNESDAY. BUT MODELS THEN START SHIFTING INTO MORE OF A SOUTHWEST FLOW BY MID TO LATE WEEK BRINGING INCREASED PRECIPITATION CHANCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 556 PM CDT FRI AUG 15 2014 THUNDERSTORM POTENTIAL WILL HIGHLIGHT THE 00 UTC TAF CYCLE. KDIK/KBIS/KISN HAVE THE BEST POTENTIAL TO BE IMPACTED BY STORMS WITH POSSIBLE IFR CONDITIONS. SEE TAFS FOR EXPECTED TIMING AND IMPACTS. && .BIS WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR NDZ017-018- 031>033-040-041-043-044. && $$ UPDATE...TM SHORT TERM...AYD LONG TERM...TWH AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
549 PM CDT FRI AUG 15 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 549 PM CDT FRI AUG 15 2014 HEAVY RAINFALL AND ASSOCIATED FLASH FLOODING WILL HIGHLIGHT THE SHORT TERM FORECAST. EXTENDED THE FLASH FLOOD WATCH THROUGH 12 UTC SATURDAY ACROSS THE SOUTHWEST. THE 12 UTC WRF-ARW/NMM...INCOMING 18 UTC NAM AND 16-17 UTC HRRR ITERATIONS CONTINUE TO FOCUS RAIN SHOWERS AND THUNDERSTORMS WITH PROLONGED MODERATE TO HEAVY RAINFALL ACROSS THE SOUTHWEST AND FAR SOUTH CENTRAL LATE THIS AFTERNOON AND INTO THE EARLY EVENING IN ASSOCIATION WITH THE UPPER LEVEL LOW EVIDENT ON WATER VAPOR ACROSS THE SOUTHWEST. THESE SOLUTIONS WANE CONVECTION A BIT AFTER SUNSET...THEN REDEVELOP THUNDERSTORMS ACROSS THE WEST REINVIGORATED BY INCREASING UPPER LEVEL DIFFLUENCE AND IMPULSES EJECTING OUT OF THE PACIFIC NORTHWEST CLOSED LOW. THIS IS IN AGREEMENT WITH NESDIS SATELLITE PRECIPITATION ESTIMATES AND HIGHLIGHTS FOR HEAVY RAINFALL TONIGHT. GIVEN THIS REGENERATION OF SLOW MOVING STORMS LATE TONIGHT OVER ALREADY SATURATED AREAS WITH PWATS NEAR 1.75 INCHES...THE EXTENSION OF THE WATCH IS WARRANTIED. THE 12 UTC WRF-ARW/NMM DO HIGHLIGHT SIOUX AND EMMONS COUNTIES LATE TONIGHT AS WELL FOR HEAVY RAIN...AND THIS WILL HAVE TO BE MONITORED. ADDITIONAL SCATTERED THUNDERSTORMS WITH HEAVY RAIN WILL CONTINUE ACROSS MUCH OF THE AREA SATURDAY AS THE PACIFIC NORTHWEST UPPER LEVEL LOW BEGINS TO PROPAGATE INTO THE NORTHERN PLAINS. WILL ALLOW FURTHER SHIFTS TO EVALUATE IF A FLASH FLOOD WATCH IS NEEDED. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 549 PM CDT FRI AUG 15 2014 THE MAIN FORECAST ISSUE IN THE EXTENDED PERIOD WILL CONTINUE TO BE THE THREAT OF HEAVY RAINFALL THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. DETERMINISTIC MODELS ARE IN REASONABLE AGREEMENT IN BRINGING AN UPPER LEVEL LOW CURRENTLY OVER EASTERN WASHINGTON...EAST ALONG THE INTERNATIONAL BORDER...TO THE EASTERN DAKOTAS BY MONDAY AFTERNOON. ALTHOUGH THE THREAT OF SEVERE WEATHER WILL BE LOW. WE WILL STILL NEED TO MONITOR THE THREAT OF HEAVY RAINFALL... PARTICULARLY IN THE SUNDAY NIGHT INTO EARLY MONDAY PERIOD. PERHAPS A BRIEF DRY PERIOD TUESDAY INTO EARLY WEDNESDAY. BUT MODELS THEN START SHIFTING INTO MORE OF A SOUTHWEST FLOW BY MID TO LATE WEEK BRINGING INCREASED PRECIPITATION CHANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 549 PM CDT FRI AUG 15 2014 THUNDERSTORM POTENTIAL WILL HIGHLIGHT THE 18 UTC TAF CYCLE. KDIK/KBIS/KISN HAVE THE BEST POTENTIAL TO BE IMPACTED BY STORMS WITH POSSIBLE IFR CONDITIONS. SEE TAFS FOR EXPECTED TIMING AND IMPACTS. && .BIS WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR NDZ017-018- 031>033-040-041-043-044. && $$ SHORT TERM...AYD LONG TERM...TWH AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1018 PM EDT SAT AUG 16 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 SUNDAY 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 SUNDAY 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 /02Z SUNDAY THROUGH THURSDAY/... ISOLATED TO SCATTERED LIGHT SHOWERS HAVE DEVELOPED ACRS SRN OHIO AND NRN KY IN A REGION OF ISENTROPIC LIFT. CONDITIONS ARE MAINLY VFR BUT A BRIEF MVFR VSBY RESTRICTION IS POSSIBLE IN A FEW OF THE BETTER RAIN SHOWERS. THIS LIFT SHIFTS EAST BY LATE EVENING WITH SHOWERS DIMINISHING IN COVERAGE. EXPECT EXTENSIVE VFR CLOUD COVER THRU THE NIGHT WHICH SHUD MITIGATE WIDESPREAD FOG DEVELOPMENT. HAVE A MENTION OF MVFR VSBY RESTRICTION AT BOTH KLUK AND KILN TOWARD SUNRISE. AN INCREASE IN LOW LEVEL MOISTURE AND INSTBY IS EXPECTED SUNDAY AFTN AHEAD OF LOW PRESSURE TRACKING SLOWLY EAST INTO THE LOWER OHIO RIVER VALLEY. HAVE A MENTION OF VCTS SUNDAY AFTN AT ALL BUT KCMH AND KLCK TAF SITES DUE TO EXPECTED SCATTERED CONVECTION. WINDS WILL BE OUT OF THE SOUTHWEST AROUND 10 KNOTS EARLY THIS EVENING BECOMING LIGHT SOUTH/SE OVERNIGHT AND THEN SOUTH AT 10 KTS OR LESS ON SUNDAY. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY NIGHT THROUGH WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...AR SHORT TERM...BINAU LONG TERM...JGL AVIATION...AR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
921 PM EDT SAT AUG 16 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 SUNDAY 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 SUNDAY 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 /00Z SUNDAY THROUGH THURSDAY/... A COLD FRONT JUST NORTH OF DTW WILL MOVE SOUTH ACROSS THE AREA THRU 18Z SUN. SCT SHRA ARE EXPECTED ALONG WITH POSSIBLE THUNDER. A BAND OF MVFR AND SOME LOCAL IFR CLOUDS AND FOG WILL ALSO BE DROPPING SOUTH WITH THE FRONT. THE MORE LIKELY SPOTS FOR THE IFR CIGS WILL BE YNG...CAK AND MFD BUT NOT UNTIL AFTER 09Z. SLIGHTLY DRIER AIR DRIFTING SOUTH INTO THE AREA SHOULD HELP TO IMPROVE THE LOWER CIGS AFTER 14Z...ESPECIALLY IN THE SNOWBELT AREA. THE PASSAGE OF THE FRONT WILL SHIFT SW WINDS TO MAINLY NORTH. && .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 SUNDAY FOR LEZ149. && $$ SYNOPSIS...TK NEAR TERM...KUBINA SHORT TERM...TK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
717 PM EDT SAT AUG 16 2014 .SYNOPSIS... A SLOW MOVING LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY SATURDAY EVENING 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 SUNDAY MORNING/... GOES WATER VAPOR AND VISIBLE SATELLITE IMAGERY PLACE THE CENTER OF THE WEAK CLOSED LOW OVER NORTHEAST MISSOURI THIS AFTERNOON. OUR POOL OF UNSEASONABLY LOW DEWPTS /40S/ WHICH ALLOWED FOR SEVERAL CHILLY NIGHTS WAS QUICKLY BEING REPLACED AN EQUALLY IMPRESSIVE PLUME OF ABOVE NORMAL MOISTURE POISED JUST TO THE WEST...WHERE RTMA DWPT ANALYSIS SHOWS WIDESPREAD MID 60S TO LOWER 70S DWPTS NEAR AND AHEAD OF THE INBOUND CLOSED LOW. THE 16.12Z RAOBS CLEARLY SHOWED THIS IMPRESSIVE MOISTURE GRADIENT...WITH A 0.55" PWAT AT KILN TO A 1.82" PWAT AT KILX /CENTRAL ILLINOIS/ WHICH IS ABOUT 1.5 STANDARD DEVIATIONS ABOVE CLIMO...OR ABOUT 140% NORMAL. LEADING EDGE MOISTURE TRANSPORT/THETA-E ADVECTION IS RESPONSIBLE FOR A WEAKENING AREA OF SPRINKLES/VERY LIGHT SHOWERS ALONG AND NORTH OF I-70 TODAY AND THIS WILL CONTINUE TO PETER OUT AS OUTRUNS THE BETTER MOISTURE TO THE WEST. SO CARRYING SMALL CHANCES OF RAIN LATE AFTERNOON/EARLY EVENING ALONG THIS AXIS AS MANY SITES HAVE NOT BEEN MEASURING WITH THE SPRINKLES. INTO THE EVENING AND OVERNIGHT AS THE LOW CREEPS SLOWLY EASTWARD...SUBTLE MID LEVEL ENERGY SHEARING DOWNSTREAM FROM THE WOBBLY CLOSED LOW WILL INDUCE MORE SCT SHRA AND A FEW STORMS. LOCATION IS STILL VERY MUCH IN QUESTION GIVEN LACK OF APPRECIABLE LOW LEVEL FORCING. RECENT HRRR RUNS /EXPERIMENTAL ESRL AND PARALLEL NCEP/ HAVE BEEN ATTEMPTING TO FOCUS LIGHT/MOD RAIN SHOWERS NEAR AND SOUTH OF THE OHIO RIVER CLOSER TO NOSE OF MODEST LOW LEVEL JET POINTING INTO SRN IND. 16.12Z ECMWF ALSO FAVORING THE SOUTH AS IS 16.12Z GFS WITH SCT SHRA. HOWEVER 16.12Z NCEP- BASED ARW-WRF...NMM-WRF...AND SREF PROBABILITIES SEEM TO BE LATCHING ONTO MORE OF A WEAK S/W DRIVEN RAIN CHANCE NORTH OF THE OHIO RIVER. THERE/S SOME SUPPORT FOR BOTH...SO AM NOT GOING TO TRY AND GET CUTE AND WILL INDICATE BROAD/MODERATE THREAT OF SHOWERS TONIGHT OVER MOST AREAS. ACTIVITY EITHER WAY WON/T BE WIDESPREAD...AND THUNDER THREATS SEEM RATHER LOW GIVEN STILL- ARRIVING INSTBY ALOFT. GIVEN THE HUGE INCREASE IN MOISTURE THAT IS OCCURRING...LOWS TONIGHT ABOUT 15 DEGREES HIGHER THAN LAST NIGHT. && .SHORT TERM /6 AM SUNDAY 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 /23Z SATURDAY THROUGH THURSDAY/... ISOLATED TO SCATTERED LIGHT SHOWERS HAVE DEVELOPED ACRS SRN OHIO AND NRN KY IN A REGION OF ISENTROPIC LIFT. CONDITIONS ARE MAINLY VFR BUT A BRIEF MVFR VSBY RESTRICTION IS POSSIBLE IN A FEW OF THE BETTER RAIN SHOWERS. THIS LIFT SHIFTS EAST BY LATE EVENING WITH SHOWERS DIMINISHING IN COVERAGE. EXPECT EXTENSIVE VFR CLOUD COVER THRU THE NIGHT WHICH SHUD MITIGATE WIDESPREAD FOG DEVELOPMENT. HAVE A MENTION OF MVFR VSBY RESTRICTION AT BOTH KLUK AND KILN TOWARD SUNRISE. AN INCREASE IN LOW LEVEL MOISTURE AND INSTBY IS EXPECTED SUNDAY AFTN AHEAD OF LOW PRESSURE TRACKING SLOWLY EAST INTO THE LOWER OHIO RIVER VALLEY. HAVE A MENTION OF VCTS SUNDAY AFTN AT ALL BUT KCMH AND KLCK TAF SITES DUE TO EXPECTED SCATTERED CONVECTION. WINDS WILL BE OUT OF THE SOUTHWEST AROUND 10 KNOTS EARLY THIS EVENING BECOMING LIGHT SOUTH/SE OVERNIGHT AND THEN SOUTH AT 10 KTS OR LESS ON SUNDAY. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY NIGHT THROUGH WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...JGL AVIATION...AR
AREA FORECAST DISCUSSION
NWS TULSA OK
1052 PM CDT SAT AUG 16 2014 .DISCUSSION... THE 06Z TAF DISCUSSION IS INCLUDED BELOW. && .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VFR CONDITIONS WILL PREVAIL AT THE TAF SITES OVER THE NEXT 24 HOURS WITH A COUPLE MINOR EXCEPTIONS. RUC MODEL TIME HEIGHT PLOTS INDICATE THE POTENTIAL FOR SOME FOG AT KBVO AND POSSIBLY AT KRVS TOWARD MORNING. THE CHANCE OF A STORM IS TOO LOW TO PUT A MENTION IN FOR THE TAFS. LACY && .PREV DISCUSSION... /ISSUED 838 PM CDT SAT AUG 16 2014/ DISCUSSION... THE CONVECTION THAT DEVELOPED EARLIER THIS AFTERNOON ALONG A WEAK SURFACE BOUNDARY ACROSS EXTREME NORTHEAST OKLAHOMA AND SOUTHEAST KANSAS HAS PRETTY WELL DISSIPATED WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WILL CONTINUE LOW POPS ACROSS THE AREA THROUGH THE NIGHT AS A MID-LEVEL SHORTWAVE MOVES ACROSS THE AREA. ONLY MADE SOME MINOR ADJUSTMENTS TO THE GRIDS FOR TONIGHT. OTHERWISE...CURRENT FORECAST LOOKS GOOD. && .PRELIMINARY POINT TEMPS/POPS... TUL 72 93 72 97 / 20 10 0 10 FSM 71 92 71 93 / 20 20 10 10 MLC 72 90 73 92 / 20 20 10 10 BVO 68 92 69 96 / 20 10 10 10 FYV 68 87 65 91 / 20 10 10 10 BYV 68 88 65 92 / 20 10 10 10 MKO 70 91 71 96 / 20 10 10 10 MIO 69 89 68 92 / 20 10 0 10 F10 71 91 71 94 / 20 10 10 10 HHW 72 89 72 94 / 30 20 10 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...30
AREA FORECAST DISCUSSION
NWS NORMAN OK
244 PM CDT FRI AUG 15 2014 .DISCUSSION... LATE TODAY THROUGH TONIGHT...A 500 MB SHORT WAVE ACROSS THE CENTRAL PLAINS WILL TRANSLATE TO THE EAST INTO THE MIDWEST. THIS WILL RESULT IN THE 500 MB RIDGE TO RETROGRADE SLIGHTLY TO THE WEST. A DIFFUSE FRONTAL BOUNDARY WILL APPROACH NORTHWEST OKLAHOMA LATER TODAY. BOTH THE NAM AND HRRR SUGGEST ISOLATED SHOWERS AND STORMS MAY DEVELOP ALONG OR AHEAD OF THE BOUNDARY LATE TODAY INTO THIS EVENING...BUT COVERAGE APPEARS TO BE LIMITED. BEST CHANCES WILL BE ACROSS THE NORTHWEST. LARGE DEW POINT DEPRESSIONS SUGGEST GUSTY WINDS WILL BE THE MAIN THREAT FROM ANY STORMS THAT DO DEVELOP. HRRR ALSO SUGGESTS A COMPLEX MAY MOVE THROUGH THE TEXAS PANHANDLE. THIS MAY CLIP EXTREME WESTERN AND SOUTHWESTERN PARTS OF THE CWA. ON SATURDAY...THE BOUNDARY WILL LIKELY BE VERY DIFFUSE. ISOLATED STORMS WILL BE POSSIBLE ACROSS THE AREA. THE BIGGER STORY WILL BE TEMPERATURES. 850MB TEMPERATURES ARE PROGGED TO BE BETWEEN 25 TO 28C ACROSS THE CWA. AS A RESULT...SATURDAY MIGHT BE THE HOTTEST DAY IN FORECAST THE PERIOD. MANY AREAS WILL SEE AT LEAST 100 DEGREE HEAT. BEYOND SATURDAY...THE CWA APPEARS TO BE WITHIN A WEAKNESS IN THE RIDGE. ISOLATED THUNDERSTORMS CAN NOT BE RULED OUT ALMOST ANY DAY THROUGH AT LEAST MID-WEEK. TEMPERATURES LOOK TO BE SEASONABLY HOT...THOUGH NOT AS HOT AS SATURDAY. THE RIDGE MAY TRY TO BUILD INTO THE REGION BY LATE NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 74 99 74 98 / 10 20 20 20 HOBART OK 73 100 73 98 / 10 20 20 20 WICHITA FALLS TX 76 99 77 98 / 10 20 20 20 GAGE OK 68 101 69 98 / 20 20 20 20 PONCA CITY OK 74 98 72 98 / 20 20 20 20 DURANT OK 73 97 76 96 / 10 20 20 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 30/10/84
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1122 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT OVER THE GREAT LAKES THIS EVENING WILL MOVE SOUTH AND THROUGH PENNSYLVANIA SUNDAY. THIS FRONT WILL BECOME NEARLY STATIONARY JUST SOUTH OF THE PA BORDER AND ACT AS THE FOCUS FOR UNSETTLED CONDITIONS THAT COULD LAST MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... RADAR CONTINUES TO SHOW SCATTERED SHOWER STREAK SE OUT OF NY AND THE LOWER LAKES. FINALLY SEE SOME RAIN REACHING THE GROUND AT MEADVILLE...BUT STILL DRY IN MOST LOCATIONS. THE HRRR IS KEEPING WITH THE IDEA OF A RELATIVELY NARROW BAND OF SHOWERS DROPPING SOUTH OVERNIGHT...WITH THE BEST CHANCE OF MEASURABLE RAIN REMAINING ALONG AND NORTH OF I-80. RAIN SHOULD SETTLE SOUTH AND DWINDLE IN COVERAGE AFTER 06Z...AS THE SHORTWAVE SLIDES OFF TO THE SE OF THE FCST AREA. DRIER CONDITIONS WILL SETTLE IN FROM THE NORTH. TONIGHT`S LOWS GENERALLY IN THE 50S WILL BE VERY NEAR SEASONAL NORMALS. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... THE WEAK FRONT WILL BECOME PRETTY MUCH STATIONARY IN THE WNW UPPER FLOW ALONG OR JUST SOUTH OF THE MASON-DIXON LINE DURING THE DAY SUNDAY. THIS SHOULD FAVOR SOUTHERN AREAS WITH THE BEST CHANCE OF SHOWERS THROUGHOUT THE DAY. THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN CENTRAL/SOUTHERN PA IN THE MORNING WITH ACTIVITY MOVING SOUTH FOR THE BULK OF THE REST OF THE DAY. TEMPERATURES IN THE 70S TO LOWER 80S...WHILE PROBABLY FEELING WARM RELATIVE TO RECENT CONDITIONS...WILL STILL AVERAGE A BIT BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON. SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY INTO TUESDAY. THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT. LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH THIS PERIOD. THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO NEXT WEEKEND. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA LATE TONIGHT...ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF PRE-DAWN LOW CIGS AT KBFD...CAUSED BY PLUME OF PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIGNIFICANT RESTRICTIONS MUCH LESS LIKELY. DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. 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. SLGHT 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...LA CORTE NEAR TERM...LA CORTE SHORT TERM...GRUMM LONG TERM...GRUMM/CERU AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1027 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT OVER THE GREAT LAKES THIS EVENING WILL MOVE SOUTH AND THROUGH PENNSYLVANIA SUNDAY. THIS FRONT WILL BECOME NEARLY STATIONARY JUST SOUTH OF THE PA BORDER AND ACT AS THE FOCUS FOR UNSETTLED CONDITIONS THAT COULD LAST MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... RADAR CONTINUES TO SHOW SCATTERED SHOWER STREAK SE OUT OF NY AND THE LOWER LAKES. FINALLY SEE SOME RAIN REACHING THE GROUND AT MEADVILLE...BUT STILL DRY IN MOST LOCATIONS. THE HRRR IS KEEPING WITH THE IDEA OF A RELATIVELY NARROW BAND OF SHOWERS DROPPING SOUTH OVERNIGHT...WITH THE BEST CHANCE OF MEASURABLE RAIN REMAINING ALONG AND NORTH OF I-80. RAIN SHOULD SETTLE SOUTH AND DWINDLE IN COVERAGE AFTER 06Z...AS THE SHORTWAVE SLIDES OFF TO THE SE OF THE FCST AREA. DRIER CONDITIONS WILL SETTLE IN FROM THE NORTH. TONIGHT`S LOWS GENERALLY IN THE 50S WILL BE VERY NEAR SEASONAL NORMALS. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... THE WEAK FRONT WILL BECOME PRETTY MUCH STATIONARY IN THE WNW UPPER FLOW ALONG OR JUST SOUTH OF THE MASON-DIXON LINE DURING THE DAY SUNDAY. THIS SHOULD FAVOR SOUTHERN AREAS WITH THE BEST CHANCE OF SHOWERS THROUGHOUT THE DAY. THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN CENTRAL/SOUTHERN PA IN THE MORNING WITH ACTIVITY MOVING SOUTH FOR THE BULK OF THE REST OF THE DAY. TEMPERATURES IN THE 70S TO LOWER 80S...WHILE PROBABLY FEELING WARM RELATIVE TO RECENT CONDITIONS...WILL STILL AVERAGE A BIT BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON. SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY INTO TUESDAY. THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT. LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH THIS PERIOD. THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO NEXT WEEKEND. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... WIDESPREAD VFR CONDS ACROSS CENTRAL PA AS OF EARLY EVENING. A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA TONIGHT...ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF LOW CIGS AT KBFD LATE TONIGHT...CAUSED BY PLUME OF PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIG RESTRICTIONS MUCH LESS LIKELY. DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. 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. SLGHT 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...LA CORTE NEAR TERM...LA CORTE SHORT TERM...GRUMM LONG TERM...GRUMM/CERU AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
746 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT OVER THE GREAT LAKES THIS EVENING WILL MOVE SOUTH AND THROUGH PENNSYLVANIA SUNDAY. THIS FRONT WILL BECOME NEARLY STATIONARY JUST SOUTH OF THE PA BORDER AND ACT AS THE FOCUS FOR UNSETTLED CONDITIONS THAT COULD LAST MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... SHOWER ACTIVITY...AT LEAST THE RADAR RETURNS...IS BEGINNING TO INCREASE OVER MY FAR NORTHERN ZONES. SO FAR NO OBS IN PA INDICATE RAIN REACHING THE GROUND. THE HRRR SUGGESTS SHOWER ACTIVITY CONTINUES OVER THE NEXT COUPLE OF HOURS...AND EVEN INCREASES THROUGH MIDNIGHT...MAINLY ALONG AND NORTH OF I-80. RAIN SHOULD SETTLE SOUTH AND DWINDLE IN COVERAGE AFTER 06Z...AS THE SHORTWAVE SLIDES OFF TO THE SE OF THE FCST AREA. DRIER CONDITIONS WILL SETTLE IN FROM THE NORTH. TONIGHT`S LOWS GENERALLY IN THE 50S WILL BE VERY NEAR SEASONAL NORMALS. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... THE WEAK FRONT WILL BECOME PRETTY MUCH STATIONARY IN THE WNW UPPER FLOW ALONG OR JUST SOUTH OF THE MASON-DIXON LINE DURING THE DAY SUNDAY. THIS SHOULD FAVOR SOUTHERN AREAS WITH THE BEST CHANCE OF SHOWERS THROUGHOUT THE DAY. THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN CENTRAL/SOUTHERN PA IN THE MORNING WITH ACTIVITY MOVING SOUTH FOR THE BULK OF THE REST OF THE DAY. TEMPERATURES IN THE 70S TO LOWER 80S...WHILE PROBABLY FEELING WARM RELATIVE TO RECENT CONDITIONS...WILL STILL AVERAGE A BIT BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON. SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY INTO TUESDAY. THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT. LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH THIS PERIOD. THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO NEXT WEEKEND. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... WIDESPREAD VFR CONDS ACROSS CENTRAL PA AS OF EARLY EVENING. A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA TONIGHT...ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF LOW CIGS AT KBFD LATE TONIGHT...CAUSED BY PLUME OF PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIG RESTRICTIONS MUCH LESS LIKELY. DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. 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. SLGHT 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/LA CORTE NEAR TERM...GRUMM/LA CORTE SHORT TERM...GRUMM LONG TERM...GRUMM/CERU AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
721 PM EDT SAT AUG 16 2014 .SYNOPSIS... A COLD FRONT OVER THE GREAT LAKES THIS EVENING WILL MOVE SOUTH AND THROUGH PENNSYLVANIA SUNDAY. THIS FRONT WILL BECOME NEARLY STATIONARY JUST SOUTH OF THE PA BORDER AND ACT AS THE FOCUS FOR UNSETTLED CONDITIONS THAT COULD LAST MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... SHOWER ACTIVITY...AT LEAST THE RADAR RETURNS...IS BEGINNING TO INCREASE OVER MY FAR NORTHERN ZONES. SO FAR NO OBS IN PA INDICATE RAIN REACHING THE GROUND. THE HRRR SUGGESTS SHOWER ACTIVITY CONTINUES OVER THE NEXT COUPLE OF HOURS...AND EVEN INCREASES THROUGH MIDNIGHT...MAINLY ALONG AND NORTH OF I-80. RAIN SHOULD SETTLE SOUTH AND DWINDLE IN COVERAGE AFTER 06Z...AS THE SHORTWAVE SLIDES OFF TO THE SE OF THE FCST AREA. DRIER CONDITIONS WILL SETTLE IN FROM THE NORTH. TONIGHT`S LOWS GENERALLY IN THE 50S WILL BE VERY NEAR SEASONAL NORMALS. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... THE WEAK FRONT WILL BECOME PRETTY MUCH STATIONARY IN THE WNW UPPER FLOW ALONG OR JUST SOUTH OF THE MASON-DIXON LINE DURING THE DAY SUNDAY. THIS SHOULD FAVOR SOUTHERN AREAS WITH THE BEST CHANCE OF SHOWERS THROUGHOUT THE DAY. THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN CENTRAL/SOUTHERN PA IN THE MORNING WITH ACTIVITY MOVING SOUTH FOR THE BULK OF THE REST OF THE DAY. TEMPERATURES IN THE 70S TO LOWER 80S...WHILE PROBABLY FEELING WARM RELATIVE TO RECENT CONDITIONS...WILL STILL AVERAGE A BIT BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON. SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY INTO TUESDAY. THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT. LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH THIS PERIOD. THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO NEXT WEEKEND. && .AVIATION /23Z SATURDAY THROUGH THURSDAY/... WIDESPREAD VFR CONDS ACROSS CENTRAL PA AS OF EARLY EVENING. A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA TONIGHT...ACCOMPANIED BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE POTENTIAL OF LOW CIGS AT KBFD LATE TONIGHT...CAUSED BY PLUME OF PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA. THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIG RESTRICTIONS MUCH LESS LIKELY. DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. 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 POSSIBLE N MTNS...THEN ISOLATED SHOWERS. TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/LA CORTE NEAR TERM...GRUMM/LA CORTE SHORT TERM...GRUMM LONG TERM...GRUMM/CERU AVIATION...GRUMM/FITZGERALD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
334 PM CDT FRI AUG 15 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 333 PM CDT FRI AUG 15 2014 AT THE SURFACE...WEAK LOW LEVEL CONVERGENCE AXIS ALONG THE FAR WESTERN BORDER OF CWA THIS EVENING...WITH UPPER LEVELS FEATURING DEFORMATION AXIS ALONG WITH SEVERAL WEAK WAVES WERE PRESENT OVER THE NORTHERN PLAINS. ATMOSPHERE REMAINS VERY MOIST WITH PRECIPITABLE WATER FROM 1.5 TO 1.8 INCHES...BUT OVERALL INSTABILITY IS FAIRLY MEAGER /500-1000 J/KG AT MOST/ AND CLOUDS AND PRECIP HAVE KEPT A LITTLE CAPPING IN PLACE TOWARD SURFACE BASED CONVECTION. WITH THERMAL ADVECTION FAIRLY UNFOCUSED OVER THE NEXT 12-24 HOURS...PRETTY MUCH FOLLOWED THE LOCATION OF THE MID LEVEL VORTICITY AXIS TO MAP PRECIPITATION CHANCES THROUGH THE IMMEDIATE TERM. HOWEVER...FOR THIS EVENING...THE SUBTROPICAL PORTION OF WAVE WILL BEGIN TO SINK SOUTHEAST ACROSS NEBRASKA EARLY THIS EVENING...AND LEAVE MUCH OF THE AREA IN WEAK TO NON EXISTENT FORCING BETWEEN THE FIRST IMPULSE LOCATED ALONG THE VORTEX AXIS IN IOWA...AND THE SECOND WANDERING IN WESTERN NORTH DAKOTA. LOCATION OF SUCH FICKLE FEATURES WILL PRETTY MUCH DRIVE THE MORE CONCENTRATED CHANCES FOR PRECIPITATION OVER THE NEXT DAY. ERRONEOUS INSTABILITY APPEARS TO BE THE CULPRIT FOR VARIOUS SHORT TERM HIGH RESOLUTION MODELS IN PRECIPITATION DEVELOPMENT...AND HAVE SHOWN SOME PREFERENCE TO OVERALL DRIER SUGGESTED BY HRRR WHICH PRETTY HAS TRENDED TO HAVING MUCH OF ANY THREAT FOR PRECIP BY EARLY EVENING. WEAK MEAN WIND SPEEDS WILL ALSO MEAN THAT PRECIPITATION WILL NOT SO MUCH MOVE INTO ANY AREA AND WILL HAVE TO DEVELOP IN PLACE. STRATUS EXPECTED TO DEVELOP LATER IN THE NIGHT WITH WEAK FLOW AND ABUNDANT LOW LEVEL MOISTURE...WHICH WILL IMPACT POTENTIAL FOR TEMPS ON SATURDAY. WHILE TEMPS LARGELY DEPENDENT ON CLOUDS/PRECIP...HAVE SIDED SOMEWHAT COOLER THAN MEAN GUIDANCE...ESPECIALLY IN MORE PRECIPITATION FAVORED WEST/JAMES VALLEY. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 333 PM CDT FRI AUG 15 2014 ON SATURDAY NIGHT...FOLLOWED A 500MB VORT FILAMENT AS IT MOVES EASTWARD ACROSS OUR FORECAST AREA AS GUIDANCE FOR TIMING AND PLACEMENT OF CONVECTIVE CHANCES. THE 500MB FLOW IS STRONGLY DIFFLUENT...WITH NOT A LOT OF WIND UPSTAIRS TO PUSH THE INDIVIDUAL CELLS EASTWARD. COUPLED WITH THE DAYTIME HEATING...THOUGHTS ARE THAT LOW END LIKELY POPS ARE WARRANTED FROM THE JAMES RIVER VALLEY TO I 29 IN SOUTH DAKOTA...PLACED SQUARELY ON THE VORT FILAMENT IN THE EARLY EVENING. POPS THEN RAPIDLY DECREASE HEADING EAST OF I 29 AS THE FORCING MECHANISM COMES TO A HALT. AFTER EARLY EVENING...THE CHANCE FOR RAIN WILL LIKELY WIND DOWN AS WE LOSE HEATING...COUPLED WITH THE FACT THAT THE VORT FILAMENT ALSO WEAKENS AS IT MOVES EASTWARD ACROSS OUR FORECAST AREA. SUNDAYS PRECIP CHANCES ARE DIFFICULT TO FIGURE OUT. BUT IN GENERAL IT APPEARS THAT CHANCE POPS ARE WARRANTED MAINLY EAST OF I 29 ALONG THE DIFFLUENT FLOW ALOFT...AND KEPT THINGS DRY IN OUR FAR WESTERN ZONES. HIGHS AND LOWS SUNDAY AND SATURDAY NIGHT LOOK NON EVENTFUL FOR THIS TIME OF YEAR...WITH 60S PRESENT SATURDAY NIGHT...AND UPPER 70S TO MID 80S ON SUNDAY. THE NEXT WAVE WE CAN FOLLOW IS A SYNOPTIC SCALE FEATURE WHICH THE VARIOUS MODELS MOVE ACROSS OUR AREA LATE SUNDAY NIGHT AND MONDAY MORNING. LIKELY POPS ARE WARRANTED FOR MOST LOCATIONS. SEVERE CHANCES ARE NOT REAL GREAT BECAUSE MUCH OF THE CONVECTION SHOULD REMAIN WEST OF OUR FORECAST AREA SUNDAY EVENING...AND THE MID LEVEL WIND SHEAR IS NOT REAL STRONG. IN THE EXTENDED PORTION OF THE FORECAST BEGINNING MONDAY NIGHT... THE DETERMINISTIC MODELS ARE IN PRETTY GOOD AGREEMENT IN DROPPING THE UPPER LOW/TROUGH THROUGH THE EASTERN PLAINS...PRIMARILY IN THE FAR EASTERN DAKOTAS...MINNESOTA AND IOWA. A CORRESPONDING SURFACE WIND SHIFT TO A NORTHWESTERLY DIRECTION FOLLOWS SUIT LATE MONDAY NIGHT AND TUESDAY. THEN THE UPPER TROUGH EVER SO SLOWLY MOVES EASTWARD INTO THE GREAT LAKES REGION BY WEDNESDAY. THIS IS WHERE MODEL DISCREPANCY BEGINS...AT LEAST BETWEEN THE DETERMINISTIC GFS AND ECMWF IN HOW QUICKLY THEY ADVANCE THE NEXT UPPER TROUGH EASTWARD ACROSS THE PACIFIC NORTHWEST. THE ECMWF ACTUALLY SHOWS TWO WAVES... WITH ONE PASSING QUICKLY EASTWARD IN OUR AREA WEDNESDAY NIGHT...AND A SECOND ONE FOLLOWING THEREAFTER. THE GFS MORPHS EVERYTHING INTO ONE LARGER WAVE WEST OF OUR FORECAST AREA. THE GEM GLOBAL IS OFF ON ITS OWN. ALL IN ALL...IT APPEARS CHANCES FOR CONVECTION ARE NOT REAL GREAT MONDAY NIGHT THROUGH FRIDAY. WITH THIS MUCH DISCREPANCY... ENSEMBLE BLENDING IS THE WAY TO GO BUT DID PUT SOME CREDENCE IN THE ECMWF WAVE PASSAGE WEDNESDAY NIGHT...WHICH GIVE DECENT CHANCE POPS FOR MUCH OF OUR AREA. OTHERWISE FOR TEMPERATURES...LOOKS LIKE A LOT OF 60S FOR LOWS AND 80S FOR HIGHS...WITH 850MB TEMPERATURES NOT REAL NOTEWORTHY ONE WAY OR ANOTHER. IT DOES LOOK HUMID THROUGH THE EXTENDED PERIOD...EVEN ON TUESDAY WHEN THE LIGHT NORTHWEST SURFACE FLOW OCCURS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1152 AM CDT FRI AUG 15 2014 CONVECTION SHOULD CONTINUE TO BE THE LARGEST ISSUE WITH AVIATION FORECASTS THROUGH THE NEXT 24 HOURS. MODELS STRUGGLING WITH THE OVERALL WEAKLY FORCED AND WEAKLY UNSTABLE ATMOSPHERE. LIKELY TO GET AN AFTERNOON ENHANCEMENT ALONG AND WEST OF A KHON TO KFSD TO KSLB LINE...WITH LIKELY BRIEF MVFR CEILINGS AND VISIBILITIES. INDICATIONS ARE THAT ACTIVITY WILL WANE BY AROUND 06Z IN THIS AXIS...BUT UNTIL THEN...SLOW MOVEMENT WILL MEAN IMPACTED AREAS MAY BE THAT WAY FOR SEVERAL HOURS. LATER IN THE OVERNIGHT AND SATURDAY MORNING SUGGEST BLOSSOMING OF MVFR TO IFR STRATUS AS PRECIPITATION THREAT WINDS DOWN. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...MJ AVIATION...CHAPMAN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1125 AM MDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1015 AM MDT FRI AUG 15 2014 UPDATED FORECAST TO REMOVE FLASH FLOOD WATCH AND TO LOWER HIGHS ACROSS PORTIONS OF THE AREA FOR TODAY. SCATTERED SHOWERS ARE MOVING EAST OF THE AREA WITH A FEW LIGHT SHOWERS REMAINING OVER NORTHWESTERN SOUTH DAKOTA. HRRR AND LOCAL WRF MODELS HAVE DECREASED THE INTENSITY OF THE RAINFALL THROUGH THE AFTERNOON WITH THE LATEST NAM INDICATING LOWERING OF PW VALUES. THUS CANCELLED FLASH FLOOD WATCH WITH THIS UPDATE. CLOUD COVER AND SHOWERS WILL KEEP HIGH TEMPERATURES LOWER THAN ORIGINALLY FORECAST...THUS LOWERED HIGHS FOR TODAY AS WELL. && .SHORT TERM...TODAY THROUGH SATURDAY NIGHT ISSUED AT 337 AM MDT FRI AUG 15 2014 UPPER LEVEL ANALYSIS HAS WEAK RIDGING ACROSS THE SOUTHERN CONUS WITH STRONG SHORTWAVE MOVING THROUGH THE RIDGE ACROSS THE NORTHERN PLAINS...AND STRONGER UPPER LOW SPINNING ACROSS THE PACIFIC NORTHWEST. SKIES ARE MOSTLY CLEAR TO THE WEST OF THE BLACK HILLS AND MOSTLY CLOUDY TO THE EAST. MAIN BATCH OF SHOWERS AND THUNDERSTORMS HAVE LIFTED INTO NORTHWEST SOUTH DAKOTA...WITH SOME WEAK RETURNS SHOWING UP ACROSS SOUTH CENTRAL SOUTH DAKOTA AND NORTHERN NEBRASKA. AT THE SURFACE...BROAD AREA OF LOW PRESSURE STRETCHES FROM WESTERN NORTH DAKOTA TO WESTERN KANSAS. TEMPERATURES AT 3 AM ARE IN THE 60S TO LOWER 70S. TODAY...STRONG SHORTWAVE THAT BROUGHT SHOWERS AND THUNDERSTORMS TO THE AREA YESTERDAY...WILL SLIDE SLOWLY EAST ALONG THE SD/ND BORDER TODAY. SURFACE BOUNDARY ACROSS CENTRAL SD WILL NOT MOVE MUCH...SO EAST TO SOUTHEAST BOUNDARY LAYER FLOW WILL CONTINUE TO BRING MOISTURE INTO NORTHERN AND EASTERN PORTIONS OF THE FORECAST AREA TODAY. PW`S REMAIN HIGH ACROSS THIS AREA...SO HEAVY RAINS WILL STILL BE A CONCERN TODAY...FROM NORTHWEST THROUGH SOUTH CENTRAL SOUTH DAKOTA. A FLASH FLOOD WATCH WILL REMAIN IN EFFECT FOR THESE AREAS THROUGH LATE THIS AFTERNOON. HIGH TEMPERATURES WILL CLIMB INTO THE MID 70S TO MID 80S. TONIGHT...UPPER SHORTWAVE WILL SLOWLY PUSH INTO EASTERN SOUTH DAKOTA AS WEAK SURFACE HIGH MOVES INTO EASTERN MONTANA. SCATTERED SHOWERS AND THUNDERSTORMS WILL STILL BE POSSIBLE ACROSS NORTHWEST INTO SOUTH CENTRAL SOUTH DAKOTA...WITH HEAVY RAIN THREAT DIMINISHING THROUGH THE EVENING. LOW TEMPERATURES WILL FALL INTO THE MID 50S TO MID 60S. SATURDAY...SHORTWAVE UPPER RIDGE TRIES TO BUILD INTO WESTERN AREAS AS SHORTWAVE TROF SHIFTS EAST. ANTECEDENT MOISTURE...SURFACE HEATING...AND WEAK ENERGY MOVING ACROSS THE NORTHERN PLAINS MAY PRODUCE AN ISOLATED STORM OR TWO...BUT MAINLY DRY CONDITIONS SHOULD PREVAIL. HIGH TEMPERATURES WILL BE IN THE UPPER 70S TO UPPER 80S. ISOLATED SHOWERS MAY PERSIST INTO THE EVENING ACROSS THE BLACK HILLS INTO NORTHWEST SOUTH DAKOTA. LOW TEMPERATURES WILL FALL INTO THE MID 50S TO MID 60S. && .LONG TERM...SUNDAY THROUGH THURSDAY ISSUED AT 337 AM MDT FRI AUG 15 2014 SUNDAY/MONDAY WILL FEATURE WESTERLY FLOW ALOFT AS A COUPLE OF SHORTWAVE TROUGHS MOVES ACROSS THE NORTHERN PLAINS. BEST POPS APPEAR TO BE DURING PEAK HEATING SUNDAY AFTERNOON/EVENING WITH SUFFICIENT CAPE/SHEAR ON THE SD PLAINS FOR ISOLATED SEVERE STORMS. UPPER LEVEL PATTERN THEN TRANSITIONS FOR NEXT WEEK WITH DEVELOPING LARGE SCALE UPPER TROUGH OVER WESTERN NORTH AMERICA. RESULT FOR CWA WILL BE A SHIFT TO SOUTHWEST FLOW ALOFT...WITH THE STRENGTH OF RIDGING OVER THE CENTRAL US DEPENDENT ON WHETHER YOU BUY THE 00Z GFS OR ECMWF. ECMWF WEAKEST WITH UPPER RIDGE. SPLIT THE DIFFERENCE WHICH MEANS SEASONAL TEMPERATURES AND LOWISH POPS GIVEN DRIER AIR MIXING OUT ACROSS PORTIONS OF THE CWA FROM THE HIGHER TERRAIN TO OUR WEST. && .AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY ISSUED AT 1115 AM MDT FRI AUG 15 2014 SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE REGION THIS AFTERNOON AND EVENING. THE BEST CHANCE OF PRECIPITATION WILL BE OVER NORTHWESTERN SOUTH DAKOTA. THE PRECIPITATION WILL END FROM WEST TO EAST THIS EVENING. AREAS OF MVFR CIGS WILL BE FOUND OVER PARTS OF FAR NORTHWESTERN SOUTH DAKOTA THROUGH MUCH OF THE AFTERNOON. AFTER MIDNIGHT...MORE WIDEPSREAD MVFR CIGS WILL DEVELOP OVER PARTS OF WESTERN SOUTH DAKOTA. CONDITIONS WILL IMPROVE TO VFR AGAIN BY MID MORNING ON SATURDAY. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...MLS SHORT TERM...15 LONG TERM...HELGESON AVIATION...10
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1021 AM MDT FRI AUG 15 2014 .UPDATE... ISSUED AT 1015 AM MDT FRI AUG 15 2014 UPDATED FORECAST TO REMOVE FLASH FLOOD WATCH AND TO LOWER HIGHS ACROSS PORTIONS OF THE AREA FOR TODAY. SCATTERED SHOWERS ARE MOVING EAST OF THE AREA WITH A FEW LIGHT SHOWERS REMAINING OVER NORTHWESTERN SOUTH DAKOTA. HRRR AND LOCAL WRF MODELS HAVE DECREASED THE INTENSITY OF THE RAINFALL THROUGH THE AFTERNOON WITH THE LATEST NAM INDICATING LOWERING OF PW VALUES. THUS CANCELLED FLASH FLOOD WATCH WITH THIS UPDATE. CLOUD COVER AND SHOWERS WILL KEEP HIGH TEMPERATURES LOWER THAN ORIGINALLY FORECAST...THUS LOWERED HIGHS FOR TODAY AS WELL. && .SHORT TERM...TODAY THROUGH SATURDAY NIGHT ISSUED AT 337 AM MDT FRI AUG 15 2014 UPPER LEVEL ANALYSIS HAS WEAK RIDGING ACROSS THE SOUTHERN CONUS WITH STRONG SHORTWAVE MOVING THROUGH THE RIDGE ACROSS THE NORTHERN PLAINS...AND STRONGER UPPER LOW SPINNING ACROSS THE PACIFIC NORTHWEST. SKIES ARE MOSTLY CLEAR TO THE WEST OF THE BLACK HILLS AND MOSTLY CLOUDY TO THE EAST. MAIN BATCH OF SHOWERS AND THUNDERSTORMS HAVE LIFTED INTO NORTHWEST SOUTH DAKOTA...WITH SOME WEAK RETURNS SHOWING UP ACROSS SOUTH CENTRAL SOUTH DAKOTA AND NORTHERN NEBRASKA. AT THE SURFACE...BROAD AREA OF LOW PRESSURE STRETCHES FROM WESTERN NORTH DAKOTA TO WESTERN KANSAS. TEMPERATURES AT 3 AM ARE IN THE 60S TO LOWER 70S. TODAY...STRONG SHORTWAVE THAT BROUGHT SHOWERS AND THUNDERSTORMS TO THE AREA YESTERDAY...WILL SLIDE SLOWLY EAST ALONG THE SD/ND BORDER TODAY. SURFACE BOUNDARY ACROSS CENTRAL SD WILL NOT MOVE MUCH...SO EAST TO SOUTHEAST BOUNDARY LAYER FLOW WILL CONTINUE TO BRING MOISTURE INTO NORTHERN AND EASTERN PORTIONS OF THE FORECAST AREA TODAY. PW`S REMAIN HIGH ACROSS THIS AREA...SO HEAVY RAINS WILL STILL BE A CONCERN TODAY...FROM NORTHWEST THROUGH SOUTH CENTRAL SOUTH DAKOTA. A FLASH FLOOD WATCH WILL REMAIN IN EFFECT FOR THESE AREAS THROUGH LATE THIS AFTERNOON. HIGH TEMPERATURES WILL CLIMB INTO THE MID 70S TO MID 80S. TONIGHT...UPPER SHORTWAVE WILL SLOWLY PUSH INTO EASTERN SOUTH DAKOTA AS WEAK SURFACE HIGH MOVES INTO EASTERN MONTANA. SCATTERED SHOWERS AND THUNDERSTORMS WILL STILL BE POSSIBLE ACROSS NORTHWEST INTO SOUTH CENTRAL SOUTH DAKOTA...WITH HEAVY RAIN THREAT DIMINISHING THROUGH THE EVENING. LOW TEMPERATURES WILL FALL INTO THE MID 50S TO MID 60S. SATURDAY...SHORTWAVE UPPER RIDGE TRIES TO BUILD INTO WESTERN AREAS AS SHORTWAVE TROF SHIFTS EAST. ANTECEDENT MOISTURE...SURFACE HEATING...AND WEAK ENERGY MOVING ACROSS THE NORTHERN PLAINS MAY PRODUCE AN ISOLATED STORM OR TWO...BUT MAINLY DRY CONDITIONS SHOULD PREVAIL. HIGH TEMPERATURES WILL BE IN THE UPPER 70S TO UPPER 80S. ISOLATED SHOWERS MAY PERSIST INTO THE EVENING ACROSS THE BLACK HILLS INTO NORTHWEST SOUTH DAKOTA. LOW TEMPERATURES WILL FALL INTO THE MID 50S TO MID 60S. && .LONG TERM...SUNDAY THROUGH THURSDAY ISSUED AT 337 AM MDT FRI AUG 15 2014 SUNDAY/MONDAY WILL FEATURE WESTERLY FLOW ALOFT AS A COUPLE OF SHORTWAVE TROUGHS MOVES ACROSS THE NORTHERN PLAINS. BEST POPS APPEAR TO BE DURING PEAK HEATING SUNDAY AFTERNOON/EVENING WITH SUFFICIENT CAPE/SHEAR ON THE SD PLAINS FOR ISOLATED SEVERE STORMS. UPPER LEVEL PATTERN THEN TRANSITIONS FOR NEXT WEEK WITH DEVELOPING LARGE SCALE UPPER TROUGH OVER WESTERN NORTH AMERICA. RESULT FOR CWA WILL BE A SHIFT TO SOUTHWEST FLOW ALOFT...WITH THE STRENGTH OF RIDGING OVER THE CENTRAL US DEPENDENT ON WHETHER YOU BUY THE 00Z GFS OR ECMWF. ECMWF WEAKEST WITH UPPER RIDGE. SPLIT THE DIFFERENCE WHICH MEANS SEASONAL TEMPERATURES AND LOWISH POPS GIVEN DRIER AIR MIXING OUT ACROSS PORTIONS OF THE CWA FROM THE HIGHER TERRAIN TO OUR WEST. && .AVIATION...FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING ISSUED AT 337 AM MDT FRI AUG 15 2014 SCATTERED/NUMEROUS TSRA WILL PERSIST OVER NORTHWEST INTO CENTRAL SD TODAY WITH LOCAL IFR CIGS/VSBYS. AREAS MVFR ST OVER NORTHWEST SD THIS MORNING. ADDITIONAL ISOLATED/SCATTERED TSRA WILL DEVELOP TODAY OVER REST OF FORECAST AREA WITH LOCAL MVFR VSBYS. OUTSIDE OF STORMS/ST...VFR CONDITIONS WILL PREVAIL THROUGH THIS AFTERNOON. CONDITIONS WILL IMPROVE FROM WEST TO EAST TONIGHT AS ST/PRECIPITATION SLOWLY MOVES EAST. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...MLS SHORT TERM...15 LONG TERM...HELGESON AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
310 AM EDT FRI AUG 15 2014 .SHORT TERM (TODAY AND TONIGHT)... SOME CLOUDS ARE MOVING ACROSS NORTHERN PORTIONS OF THE AREA THIS MORNING IN ASSOCIATION WITH THE NOSE OF AN UPPER JET STREAK AND WEAK 500 MB VORT MAX. THE NAM CONTINUES TO SHOW SOME PRECIP IN NORTHERN AREAS THROUGH THE DAY...BUT THIS APPEARS OVERDONE WITH NO SIGNIFICANT UPSTREAM VORT MAXES OF NOTE IN WV IMAGERY AND A FORECAST SOUNDING THAT APPEARS TO BE WELL CAPPED. THE GFS AND RAP ARE DRIER...AND WILL GO IN THAT DIRECTION FOR TODAY. A WARMING TREND WILL CONTINUE AS THE 850 MB RIDGE BUILDS IN FROM THE WEST...WITH HIGHS IN THE MID TO UPPER 80S IN MOST VALLEY LOCATIONS. SOME THIN HIGH CLOUDS MAY MOVE IN TONIGHT IN THE NW FLOW ALOFT. .LONG TERM (SATURDAY THROUGH THURSDAY)... A SERIES OF SHORT-WAVE TROUGHS WILL MOVE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES/OHIO VALLEY SATURDAY THROUGH TUESDAY. THESE WAVES WILL HELP PULL MOISTURE/INSTABILITY BACK INTO THE TENNESSEE VALLEY KEEPING THE WEATHER UNSETTLED AS WELL AS PULLING OUTFLOW BOUNDARIES INTO THE AREA. WILL CALL FOR CHANCE POPS BEGINNING SUNDAY AFTERNOON. BEST CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE ACROSS THE SOUTHWEST VIRGINIA/NORTHEAST TENNESSEE AND NORTHERN PLATEAU DUE TO PROXIMITY TO UPPER DYNAMICS. EVEN THOUGH SHORT-WAVES HAVE EXITED BY WEDNESDAY AND THURSDAY... PLENTY OF MOISTURE/INSTABILITY REMAINS WITH MAINLY DIURNAL TERRAIN FORCED CONVECTION EXPECTED EACH DAY. DUE TO PERFORMANCE...WENT A COUPLE OF DEGREES COOLER THAN GFX MOS HIGHS...ESPECIALLY AT CHA. GENERALLY FOLLOWED MOS MINS THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 88 64 90 67 / 0 0 0 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 86 63 87 66 / 10 10 0 10 OAK RIDGE, TN 86 62 88 66 / 10 10 0 10 TRI CITIES AIRPORT, TN 84 57 86 61 / 10 10 0 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS/DH
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1235 AM CDT FRI AUG 15 2014 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...CLOUD COVER HAS CLEARED THIS EVENING AS THUNDERSTORM ACTIVITY QUICKLY DISSIPATED WITH LOSS OF HEATING. SKIES WILL GENERALLY REMAIN CLEAR THROUGH THE REST OF THE NIGHT...WITH SOME MINIMAL GROUND FOG POSSIBLE AT KHRL DUE TO MOIST GROUND FROM RAIN YESTERDAY. BREEZY CONDITIONS EXPECTED TOMORROW AS LOW PRESSURE DEEPENS IN WEST TEXAS. HIGHER BREEZES WILL DISRUPT THE SEABREEZE DURING THE AFTERNOON...WITH MUCH MORE ISOLATED COVERAGE...IF ANY. && .PREV DISCUSSION... /ISSUED 250 PM CDT THU AUG 14 2014/ SHORT TERM /NOW THROUGH FRIDAY NIGHT...AFTERNOON WATER VAPOR SHOWS DRY AIR MOVING THROUGH SOUTH TEXAS INTO THE NORTHERN PORTIONS OF THE CWA. CRP SOUNDING SHOWED PWATS OF 1.51 INCHES. DOWN IN THE VALLEY...MORE MOISTURE IS PRESENT WITH BRO SOUNDING OF 2.04. SEA BREEZE IS MOVING INLAND WITH A FEW SHOWERS ACROSS THE COASTAL COUNTIES. HRRR SHOWS ISOLATED SHOWERS CONTINUING ALONG THE SEA BREEZE WITH MOST ACTIVITY DONE AND OVER WITH BY EARLY EVENING. HAVE SLIGHT CHANCE POPS FOLLOWING THE SEA BREEZE THROUGH THE REST OF THE DAY. HIGHS STILL EXPECTED INTO THE MID-UPPER 90S WITH LOWER 100S ACROSS THE UPPER VALLEY. NAM 500-300MB RH SHOWS DRY AIR ENGULFING THE AREA BY MID EVENING WHICH WILL SHUT DOWN ANY PRECIP REMAINING. THEREFORE...SKIES WILL CLEAR OUT AND WINDS WILL SUBSIDE ALLOWING TEMPERATURES TO FALL INTO THE MID-UPPER 70S TO AROUND 80 DEGREES. FRIDAY A SHORTWAVE TROUGH WILL MOVE DOWN THE EASTERN SIDE OF THE RIDGE PARKED OVER THE SOUTHWEST WHICH WILL HELP STRENGTHEN SURFACE TROUGHING TO OUR WEST AND STRENGTHEN WINDS ACROSS THE AREA FRIDAY AFTERNOON THROUGH THE SHORT TERM. BREEZIER CONDITIONS EXPECTED FRIDAY AFTERNOON IN THE VALLEY AND PROGRESSES INTO THE COASTAL WATERS FRIDAY NIGHT. NOT MUCH IN THE WAY OF PRECIP FRIDAY WITH LOWERED 1000-500MB RH AND PWATS FALLING TO 1.7 INCHES. DID PUT 10 POPS FOR EAST OF HWY 281 BUT NOTHING MENTIONABLE IN THE ZONES. FAVORED THE ECMWF MOS FOR TEMPERATURES SINCE MAV/MET SEEM A LITTLE LOW FOR THIS REGIME. LONG TERM /SATURDAY THROUGH WEDNESDAY/...A PERSISTENT H5 RIDGE WILL STRETCH FROM THE DESERT SOUTHWEST TO THE FLORIDA PENINSULA AND WILL DOMINATE THE UPPER PATTERN THROUGH THE MAJORITY OF THE PERIOD. THE RIDGE WILL NATURALLY EXHIBIT WEAKNESS OVER THE WEST GULF HOWEVER... SIMPLY A REFLECTION OF THE TWO STRONGER ENDS OF THE BARBELL TO THE EAST AND WEST. SFC HIGH PRESSURE WILL BE SUPPORTED OVER THE NORTH AND EAST GULF...PROVIDING A MODERATE ANTICYCLONIC FLOW OVER THE WEST GULF AND THE CWA. DRIER AIR WILL HOLD SWAY OVER LAND AREAS WITH JUST A SILENT SLIGHT CHANCE OF RAIN FOR THE GULF THROUGH MUCH OF THE LONG TERM. AN EXCEPTION WILL BE NEXT WEDNESDAY WHEN A SLUG OF MOISTURE MOVES UP FROM THE SOUTH AND APPEARS TO HAVE ENOUGH JUICE TO JUSTIFY A NONSILENT 20 PERCENT CHANCE OF SHOWERS AND TSTMS. THIS UPTICK IN POPS REPRESENTS THE EFFECTS OF A TROPICAL WAVE MOVING INTO THE SOUTHWEST GULF AT THAT TIME. OTHERWISE...WITH SUCH CONSISTENCY IN THE FORECAST. THERE WAS NOT MUCH REASON TO CHANGE THE INHERITED FORECAST SIGNIFICANTLY. TEMPS WILL RUN SLIGHTLY ABOVE NORMAL WITH LIGHT TO MODERATE ONSHORE WINDS AND A MIX OF CLOUDS AND SUN. AFTN HEAT LOWS INLAND WILL TIGHTEN THE GRADIENT SOMEWHAT WITH BREEZY AND GUSTY WINDS SHOWING UP OVER STARR AND ZAPATA COUNTIES. NO MAJOR DIFFERENCES NOTED BETWEEN THE GFS AND ECMWF AT THIS WRITING. MARINE... NOW THROUGH FRIDAY NIGHT...WINDS WILL REMAIN LIGHT TO MODERATE WITH LOW SEAS THROUGH FRIDAY MORNING. WINDS AND SEAS WILL BEGIN TO INCREASE FRIDAY AFTERNOON AND EVENING AS LOW PRESSURE STRENGTHENS TO OUR WEST AND INTERACTS WITH HIGH PRESSURE OVER THE GULF. SMALL CRAFT EXERCISE CAUTION MAY BE NEEDED FOR THE LAGUNA FRIDAY AND THE OFFSHORE WATERS FRIDAY NIGHT SATURDAY THROUGH MONDAY...BROAD H5 RIDGING FROM THE SOUTHWEST UNITED STATES EAST ACROSS THE GULF THROUGH THE NORTH ATLANTIC WILL SUPPORT HIGH PRESSURE ACROSS THE NORTH GULF AT THE SURFACE. SLIGHTLY LOWER PRESSURE WILL PERSIST OVER THE BAY OF CAMPECHE. A SLIGHT WEAKNESS OVER THE WEST GULF SPLITTING THE MAIN RIDGE WILL KEEP THE DOOR OPEN FOR SLIGHTLY ENHANCED MARINE SHOWER AND TSTM ACTIVITY. MODERATE TO BREEZY SOUTH SOUTHEAST WINDS WILL PREVAIL WITH MODERATE SEAS OF 3 TO 4 FEET WHICH MAY INCREASE A FOOT OR SO LATE IN THE WEEKEND. SMALL CRAFT EXERCISE CAUTION CONDITIONS MAY BE POSSIBLE FROM TIME TO TIME DUE TO STRONGER WINDS. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WWW.WEATHER.GOV/BROWNSVILLE 64/51
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AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
954 PM EDT SAT AUG 16 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OVER THE REGION TONIGHT. A WARM FRONT PUSHES NORTH OF US SUNDAY...THEN A COLD FRONT FOLLOWS FOR EARLY NEXT WEEK...STALLING ACROSS THE REGION. && .NEAR TERM /THROUGH SUNDAY/... AS OF 950 PM EDT SATURDAY... ADJUSTMENTS FOR THE FORECAST FOR THE OVERNIGHT WILL REFLECT SLIGHTLY MILDER LOW TEMPERATURES ACROSS EASTERN PARTS OF THE REGION. DEW POINT VALUES HAVE BEEN RUNNING A FEW DEGREES HIGHER THAN EARLIER PROJECTIONS. WHILE WE STILL ANTICIPATE A GENERAL DECLINE THROUGH THE NIGHT...THE RESULTANT DAYBREAK VALUES MAY ALSO BE HIGHER THAN MODEL GUIDANCE. AS SUCH...HAVE TWEAKED LOWS HIGHER A BIT. LATEST HRRR AND RNK WRF-ARW GUIDANCE IS PROJECTING ARRIVING ISOLATED SHOWERS LATE TONIGHT AND EARLY SUNDAY MORNING TO ENCROACH A BIT FARTHER EAST THAN EARLIER PROJECTIONS. HAVE ADJUSTED PRECIPITATION FORECAST TO ALLOW FOR ISOLATED SHOWERS ARE FAR EAST AS THE CREST OF THE BLUE RIDGE BY DAYBREAK. NO OTHER SIGNIFICANT ADJUSTMENTS AT THIS TIME. AS OF 645 PM EDT SATURDAY... NO MAJOR CHANGES TO THE FORECAST THIS EVENING. HAVE MAINLY MADE MINOR ADJUSTMENTS TO ACCOUNT FOR THE ONGOING CONDITIONS AND EXPECTED TRENDS THROUGH THE EVENING HOURS REGARDING CLOUD COVER...TEMPERATURES AND DEW POINTS. WE STILL LOOK ON TRACK FOR AN ARRIVAL OF ISOLATED SHOWERS ACROSS SOUTHEAST WEST VIRGINIA LATE TONIGHT INTO EARLY SUNDAY MORNING WITH THE APPROACH OF AN AREA OF LOW PRESSURE IN THE LOWER OHIO VALLEY AND A COLD FRONT HEADING SOUTH THROUGH IL/IN/OH. AS OF 257 PM EDT SATURDAY... SFC HIGH WILL SLIDE EAST THIS AFTERNOON INTO TONIGHT. MID/HIGH LEVEL CIRRUS CONTINUES TO STREAM IN ALOFT ACROSS THE REGION WITH FAIR WEATHER CU DEVELOPING BENEATH. GFS...ECMWF...NAM...HRRR KEPT THE CONVECTION ASSOCIATED WITH THE FRONTAL BOUNDARY SOUTH OF OUR AREA TONIGHT. AS THE UPPER TROUGH LIFTS NORTHEAST...WEAK SURFACE FLOW WILL CONTINUE TONIGHT. ANOTHER SHORTWAVE DIGS ACROSS THE LOWER OHIO VALLEY LATE TONIGHT...WITH A WARM FRONT NOSING NWD INTO THE MID ATLANTIC. CLOUDS WILL INCREASE TONIGHT WITH THE POSSIBILITY FOR ISOLATED SHOWERS IN THE WESTERN MOUNTAINS...ESPECIALLY GREENBRIER COUNTY. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE MID 50S IN THE MOUNTAINS TO THE MID 60S IN THE PIEDMONT. ON SUNDAY MORNING...FRONTAL BOUNDARY WILL SINK SOUTHWARD FROM THE GREAT LAKES AND STALL BY SUNDAY EVENING. AS THE FRONT APPROACHES...EXPECT WIDELY SCATTERED SHOWERS AND THUNDERSTORMS TO ENTER THE FORECAST REGION FROM THE NORTHWEST AS A MINOR UPPER LEVEL DISTURBANCE PASSES ACROSS THE CENTRAL APPALACHIANS. HIGH TEMPERATURES SUNDAY AFTERNOON WILL RANGE FROM THE UPPER 70S IN THE MOUNTAINS TO NEAR 90 DEGREES IN THE PIEDMONT. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 215 PM EDT SATURDAY... WEAK WARM FRONT ACROSS THE REGION SUNDAY EVENING WILL BASICALLY FADE AS YET ANOTHER BOUNDARY APPROACHES FROM THE NORTH SUNDAY NIGHT. RIBBON OF DEEPER MOISTURE ALONG THESE FEATURES SHOULD BE ENOUGH TO KEEP ISOLATED TO SCATTERED CONVECTION GOING MAINLY OVER THE WESTERN THIRD WHERE WILL BE CLOSER TO THE UPSTREAM WAVE CROSSING THE MID MISSISSIPPI VALLEY. THIS SHOULD ACT TO ENHANCE COVERAGE LATE SUNDAY NIGHT OVER THE FAR WEST AFTER ANY ISOLATED EVENING SHRA FADE WITH LOSS OF HEATING. THEREFORE ADJUSTED HIGHER CHANCE POPS TO MAINLY THE MOUNTAINS OVERNIGHT...OTRW PC TO MOSTLY CLOUDY AND NOT AS COOL WITH LOWS MOSTLY IN THE 60S. RATHER POTENT WAVE ALOFT WITH CORRESPONDING DECENT SURFACE REFLECTION WILL MOVE EAST ALONG THE FRONT JUST NORTH OF THE AREA MONDAY BEFORE EXITING MONDAY NIGHT. GUIDANCE SHOWING DIFFERENCES WITH TIMING/STRENGTH OF THIS FEATURE BUT APPEARS ENOUGH CONSENSUS TO SEE A LEAD BAND OF SHRA/TSRA NW THIRD MONDAY MORNING WITH THE INITIAL BAND OF LIFT. BEYOND THAT THE ECMWF/UKMET HAVE BETTER COVERAGE FARTHER SOUTH ALONG THE BLUE RIDGE...AND POINTS WEST WITH THE TRAILING FRONT/SECONDARY IMPULSE...WHILE THE NAM/CMC FARTHER NORTH AND THE GFS LAGGING WEST AFTER THE EARLIER SHRA WAVE. SINCE THINKING WILL SEE A FLATTER WAVE IN THE 5H ZONAL FLOW WILL TREND TOWARD THE EURO/UKMET SOLUTIONS AND PUSH GOING LIKELY/CATEGORICAL POPS A BIT SOUTH INTO SW VA...LEAVING ONLY THE FAR SE UNDER CHANCE COVERAGE. APPEARS LACK OF DEEP INSTABILITY OUTSIDE OF THE PIEDMONT PER CLOUD COVER...AND LACK OF STRONGER WINDS ALOFT SHOULD PRECLUDE TOO MUCH OF A SEVERE THREAT BUT SOME HEAVY RAIN POTENTIAL GIVEN PWATS OF 1.5-2 INCHES. THUS WILL MENTION IN THE HWO OVER FAR SW VA INTO SE WEST VA FOR HEAVY RAIN ON MONDAY. HIGH TEMPS TRICKY MONDAY PENDING DEGREE OF SHRA/CLOUDS AS COULD SEE QUITE A RANGE FROM COOL 70S NW TO AROUND 90 SE. WAVE SHOULD PASS TO THE EAST MONDAY NIGHT AND AFTER A RESIDUAL ROUND OF CONVECTION OVER THE NORTH/EAST EXPECT SOME DRYING OVERNIGHT AS WEAK WESTERLY FLOW AND SUBSIDENCE KICK IN BEHIND THE EXITING LIFT. AGAIN TRICKY AS TO WHERE THE BEST COVERAGE WILL BE MONDAY EVENING BUT BASED ON THE LATEST ECMWF/UKMET BUMPED UP POPS TO LIKELY EAST THROUGH NORTH AND CUT TO CHANCE SOUTH. THIS FOLLOWED BY DECREASING CHANCES ACROSS THE CWA AFTER MIDNIGHT AS THE LOW SLIDES TO THE COAST LATE. LOW LEVEL MOISTURE LOOKS TO LINGER TUESDAY WHILE THE AREA SLIDES IN BETWEEN THE EXITING WAVE AND THE NEXT UPSTREAM SHORTWAVE. WITH WEAK WESTERLY FLOW AND SUBSIDENCE IN PLACE...EXPECTING ONLY SCATTERED COVERAGE MAINLY WEST AND EASTERN FRINGES TUESDAY WITH HEATING...BUT COULD BE EVEN MORE ISOLATED INTO TUESDAY EVENING PER LATEST ENSEMBLES. LEFT TEMPS CLOSE TO PREVIOUS...MOSTLY 80S EXCEPT 70S AT ELEVATION. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 100 PM EDT SATURDAY... RATHER UNCERTAIN PATTERN THROUGH THE EXTENDED WITH RESIDUAL WEAK UPPER TROFFINESS IN PLACE AND A LEFTOVER SURFACE BOUNDARY DANGLING ACROSS PARTS OF THE REGION INTO FRIDAY. THIS ALONG WITH HIGH MOISTURE LEVELS WILL KEEP THINGS UNSETTLED FOR THE MOST PART PENDING DEGREE OF DAILY CONVECTION...AND SUBSEQUENT MOVEMENT OF THE BOUNDARY ESPCLY DURING THE WEEK. LATEST OPERATIONAL SOLUTIONS CONTINUE TO DIFFER ON THE AMPLITUDE OF THE UPPER PATTERN WITH A BLENDED WEAKER ECMWF CONSENSUS APPEARING BEST GIVEN LATE AUGUST CLIMO. THIS ALONG WITH UNCERTAINTY IN LOCATIONS OF ADDED SHORTWAVE ENERGY RIDING INTO THE REGION WOULD SUPPORT MORE DIURNAL NATURE TO SHOWERS/STORMS DURING THE AFTERNOON/EVENING HOURS...AND TAPERING AT NIGHT DUE TO LOSS OF INSTABILITY. THUS WILL CONTINUE TREND OF MOSTLY CHANCE POPS WED-FRI WITH BEST COVERAGE MOUNTAINS AND SLIGHT TO LOW CHANCE COVERAGE OVERNIGHT. BY SATURDAY...THE APPROACH OF ANOTHER TROUGH/FRONT FROM THE NW MAY BE ENOUGH OF A KICKER TO PUSH THE INITIAL BOUNDARY FARTHER SE...WITH MORE OF AN IN BETWEEN SCENARIO...SO TRIMMED POPS TO LOW CHANCE/SLIGHT POPS ON DAY7 FOR NOW. TEMPS TO RETURN TO MORE NORMAL LEVELS THROUGH THE PERIOD GIVEN WEAK WESTERLY FLOW AND MOST OF THE 85H COOL ADVECTION STAYING NORTH. APPEARS WARMEST READINGS ALONG THE FRONT INTO MIDWEEK WHEN MOST WILL SEE 80S AND PERHAPS TOPPING 90 OVER THE SE. THIS BEFORE THINGS BECOME MORE OF THE WARM/MUGGY NATURE BY THE WEEKEND WITH HIGHER HUMIDITY MAKING FOR RATHER WARM LOWS IN THE 60S/NEAR 70...AND HIGHS 70S MOUNTAINS TO MID 80S PIEDMONT. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... AS OF 745 PM EDT SATURDAY... GENERALLY VFR CIGS EXPECTED THROUGH THE TAF VALID PERIOD. ALTHOUGH EXTENSIVE MID/HIGH CLOUDS WILL STREAM ACROSS THE REGION THROUGH MUCH OF THE TAF VALID PERIOD FROM UPSTREAM DISTURBANCES...THE SFC AND BL AIR MASS WILL NOT MOISTEN ENOUGH THROUGH 00Z MON TO ALLOW FOR MUCH IF ANY CLOUDS BELOW 050. BKN-OVC100-250 LIKELY THROUGH THE TAF VALID PERIOD WITH SCT-BKN050-080 POSSIBLE LATE TONIGHT/EARLY SUN MAINLY ACROSS EASTERN WV IN ASSOCIATION WITH A MID-LEVEL WAVE. A FEW SPRINKLES ARE ALSO POSSIBLE WITH THIS FEATURE IN THE 08Z-12Z TIME FRAME. BIGGER QUESTION IS WHETHER OR NOT THERE WILL BE RADIATIONAL FOG DEVELOPMENT TONIGHT AT THE USUAL SPOTS. GIVEN EXTENSIVE MID/HIGH CLOUDS...ESPECIALLY AT LWB/BCB...HAVE DECIDED BASED ON RECENT EXPERIENCES AND OTHERWISE DRY SFC/BL AIR MASS...TO BACK OFF ON FOG POTENTIAL. EVEN BUFKIT FOR LWB SHOWS VERY LITTLE FOG POTENTIAL TONIGHT. THUS...DO NOT EXPECT A REPEAT OF SATURDAY MORNINGS FOG AT LWB AND BCB. MVFR CATEGORY FOG AT WORST. WINDS GENERALLY WNW-WSW THROUGH THE TAF VALID PERIOD AT SPEEDS OF 3-7KTS. MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS 06Z-13Z...OTHERWISE HIGH CONFIDENCE IN VFR VSBYS. MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... COLD FRONT EXPECTED TO STALL NEAR OUR AREA THROUGH THE MIDDLE OF THE WEEK AS A SERIES OF UPPER-LEVEL DISTURBANCES TRACK FROM WNW- ESE ACROSS THE REGION. THE MOST POTENT DISTURBANCE APPEARS TO TRACK ACROSS THE REGION MON-TUE. THUS...WIDESPREAD SHOWERS AND THUNDERSTORMS ARE ANTICIPATED LATE MON AND MON NIGHT...EXITING TO THE EAST TUE. FOR THE REMAINDER OF THE WEEK...AN UNSTABLE NW FLOW ALOFT WILL CONTINUE ACROSS THE REGION WITH A SERIES OF UPPER DISTURBANCES. TOWARD THE END OF THE WEEK INTO NEXT WEEK...AN UPPER RIDGE WILL BUILD TO THE WEST OF THE REGION...BUT THE LOCAL AREA WILL REMAIN UNDER AN UNSTABLE NW FLOW ALOFT. DAILY CHANCES FOR SHRA/TSRA WILL CONTINUE...PRIMARILY DURING THE AFTERNOON/EVENINGS. NO DAY APPEARS RAIN FREE...BUT BY THE SAME TOKEN...CONVECTIVE ACTIVITY SHOULD REMAIN MORE SCT THROUGH THE REMAINDER OF THE WEEK. INCREASED MOISTURE AND RAIN CHANCES WILL RESULT IN A DAILY THREAT FOR LATE NIGHT/EARLY IFR-LIFR CONDITIONS IN FOG AND LOW CLOUDS AT THE USUAL SITES...LWB/BCB/LYH...WITH MVFR POSSIBLE AT OTHER LOCATIONS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KK/WP NEAR TERM...DS/KK SHORT TERM...JH LONG TERM...JH AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
332 PM EDT FRI AUG 15 2014 .SYNOPSIS... AN UPPER LEVEL DISTURBANCES WILL TRACK SOUTHEAST ACROSS OUR REGION TONIGHT. MEANWHILE...A FRONTAL ZONE STALLED OVER THE AREA WILL GRADUALLY LIFT NORTH OF THE REGION AS A WARM FRONT SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... AS OF 332 PM EDT FRIDAY... UPPER LEVEL TROUGH WILL REMAIN ALONG THE EAST COAST TONIGHT INTO SATURDAY. A SHORTWAVE WILL DROP SOUTHEAST IN THE NORTHWEST FLOW TONIGHT ACROSS THE AREA. THIS WILL COMBINE WITH A STALL FRONTAL BOUNDARY TO CREATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE UNSTABLE AIR THIS AFTERNOON INTO THIS EVENING. MSAS PLACED THE MOST UNSTABLE AIR ACROSS SOUTHWEST PORTIONS WITH LI MINUS ONE TO MINUS THREE. SPC MESOSCALE ANALYSIS HIGHLIGHTED MUCAPE ABOUT 1000 J/KG IN THE SOUTHWEST. SHAPED POPS TOWARDS HRRR FOR THIS EVENING INTO TONIGHT. SHOWERS OR STORMS SHOULD FADE TONIGHT WITH LOSS OF HEATING AND NO REAL SUPPORT ALOFT WITH TIMING CLOSE TO YESTERDAY...BECAUSE HIGHER THETA-E AIR RESIDES ACROSS THE SOUTHERN CWA INTO TONIGHT. CLEAR TO PARTLY CLOUDY CONDITIONS EXPECTED OVERNIGHT. PATCHY VALLEY FOG EXPECTED LATE TONIGHT IN THE USUAL PLACES AS WELL AS SOUTHSIDE VA/NW NC PER ANY SHOWER ACTIVITY THIS AFTERNOON/EVENING. PLAYED LOW TEMPERATURES OVERNIGHT CLOSE TO THE ADJMAVBC WITH READINGS FROM THE MID TO UPPER 40S IN THE DEEPER MOUNTAIN VALLEYS TO THE LOWER 60S IN THE SOUTHEAST...WITH HIGH PRESSURE MOVING OVERHEAD ACROSS THE CENTRAL APPALACHIANS. UPPER LEVEL TROUGHING OVER THE NORTHEAST STATES WITH GRADUALLY SHIFT EAST ON SATURDAY...RESULTING A WEAK ZONAL UPPER LEVEL PATTERN. FRONTAL BOUNDARY LIFTS NORTH ACROSS A WARM FRONT...AS A WAVE OF LOW PRESSURE MOVES ACROSS EASTERN NORTH CAROLINA AND VIRGINIA SATURDAY. MORNING LOW CLOUDS AND FOG WILL LIFT OR BURN OFF QUICKLY SATURDAY. MAY SEE AN ISOLATED SHOWER OR STORM IN THE SOUTHEAST DURING THE AFTERNOON NEAR THE FRONT...HOWEVER CHANCES APPEAR TOO LOW AT THIS POINT TO ADD MENTION IN THE FORECAST WITH LIMITED LIFT. THE DAY TWO CONVECTIVE OUTLOOK HAS PLACED THE CHANCE OF GENERAL THUNDERSTORM WAY TO OUR EAST SATURDAY ACROSS EASTERN NORTH CAROLINA. WENT WITH HIGH TEMPERATURES ON SATURDAY FROM AROUND 80 DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 301 PM EDT FRIDAY... THE FORECAST PERIOD BEGINS WITH A WEAK SURFACE HIGH OVER THE SOUTHERN APPALACHIANS AND A LEE TROUGH ACROSS THE MID ATLANTIC COASTAL PIEDMONT. BY SUNDAY AFTERNOON...THE SURFACE HIGH WITHERS AWAY WITH DIURNAL SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE MOUNTAINS. THESE STORMS ARE EXPECTED TO FADE THROUGH THE EVENING. MODELS ARE ALSO SHOWING A SHORT WAVES TRACKING EAST BUT NORTH OF THE AREA SUNDAY MORNING. THIS WAVE AND ASSOCIATED CONVECTION MAY LAY AN OUTFLOW BOUNDARY ACROSS THE MOUNTAINS TO FURTHER ENHANCE THE DEVELOPMENT OF AFTERNOON CONVECTION. SUNDAY NIGHT INTO MONDAY...MODELS ARE MOVING A MESOSCALE COMPLEX FROM THE OHIO VALLEY TO THE MID ATLANTIC REGION. THE 12Z GFS KEEPS THIS COMPLEX MOVING EAST ACROSS PENNSYLVANIA MONDAY NIGHT. THE 12Z NAM/ECM HAS A MORE SOUTHERN TRACK WITH THE COMPLEX TRACKING ACROSS WEST VIRGINIA MONDAY AND OVER CENTRAL-NORTHERN VIRGINIA MONDAY AFTERNOON/NIGHT. THIS SOUTHERN TRACK WOULD CLIP THE FORECAST AREA ALONG AND NORTH OF I64. OUTFLOW BOUNDARIES MAY GENERATE STORMS ACROSS THE REST OF THE FORECAST AREA LATE MONDAY AFTERNOON/NIGHT. SUNDAY WILL SEE TEMPERATURES WARMER THAN NORMAL WITH A SOUTHERLY FLOW AND ABUNDANT SUNSHINE. DESPITE THE COOL START TO THE MONTH...SUMMER IS NOT OVER FROM A WEATHER STAND POINT. MONDAY WILL ALSO BE A WARMER THAN NORMAL DAY...ESPECIALLY IF THE MESOSCALE COMPLEX STAYS WELL TO THE NORTH. SINCE MODELS ARE DELAYING CONVECTION ACROSS THE SOUTHERN TWO/THIRDS OF THE FORECAST AREA...WILL CONTINUE TO RUN WITH THE WARMER GUIDANCE. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 100 PM EDT FRIDAY... UNSETTLED PATTERN DURING THIS PERIOD. SEVERAL SHORTWAVES PIVOT THROUGH THE REGION TUESDAY AND WEDNESDAY AND THEN MID LEVEL RIDGING SETS UP FOR THE REST OF THE PERIOD...WITH ADDITIONAL DISTURBANCES RIDING ALONG THE RIDGE FROM THE NORTHWEST INTO OUR REGION. PLENTY OF MOISTURE AND INSTABILITY WILL BE PRESENT FOR SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. PLACED SLIGHT CHANCE TO CHANCE POPS IN EACH DAY WITH THE MAX POPS DURING THE AFTERNOON/EVENING HOURS...AND SLIGHTLY LOWER POPS DURING THE OVERNIGHT HOURS. TEMPERATURES WILL BE CLOSER TO NORMAL AS 850MB TEMPS RISE FROM +16C AT THE BEGINNING OF THE PERIOD TO NEAR +20C BY THE WEEKEND. THIS WILL COORDINATE TO SURFACE HIGH TEMPS NEAR 90 EAST OF THE BLUE RIDGE AND LOW TO MID 80S FROM THE BLUE RIDGE AND POINTS TO THE WEST. DEWPOINTS WILL HOLD IN THE MID TO UPPER 60S THROUGH THE PERIOD WHICH WILL KEEP NIGHT TIME TEMPS ON THE MILD SIDE. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... AS OF 130 PM EDT FRIDAY... SCT TO BKN MVFR CLOUDS ARE POSSIBLE ESPECIALLY IN THE WEST THIS AFTERNOON INTO TONIGHT. ISOLD MVFR CONVECTION IS POSSIBLE THIS AFTERNOON INTO THIS EVENING AS SHORTWAVE ROTATES ACROSS OUR AREA. BEST CHANCE WILL BE ACROSS SOUTHERN PORTIONS OF FORECAST AREA THIS AFTERNOON INTO TONIGHT. STORMS WILL BE TOO ISOLATED TO MENTION AT MOST TAF SITES. WINDS W TO SW WINDS MAINLY UNDER 8 KNOTS THIS AFTERNOON WILL BECOME LIGHT AND VARIABLE TONIGHT INTO SATURDAY. VFR CONDITIONS TONIGHT AS HIGH PRESSURE SINKS IN BEHIND THE UPPER SHORTWAVE. FOG WILL AGAIN FORM IN THE RIVER VALLEYS ESPECIALLY AROUND LWB/BCB. EXPECT MAINLY VFR INTO THE WEEKEND..WITH HIGH PRESSURE IN PLACE. HIGH CONFIDENCE IN CEILINGS...VISIBILITIES...AND WINDS DURING THE PERIOD. WEATHER PATTERN BECOMES MORE TYPICAL FOR AUGUST BY EARLY NEXT WEEK. LOW PROBABILITY FOR AFTERNOON AND EVENING THUNDERSTORMS...THEN FOG IN FAVORED VALLEY LOCATIONS OVERNIGHT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KK NEAR TERM...KK SHORT TERM...RCS LONG TERM...CF AVIATION...KK/WP
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
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AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1155 AM CDT FRI AUG 15 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 306 AM CDT FRI AUG 15 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW OVER THE PACIFIC NORTHWEST...RIDGING FROM THE SOUTHWESTERN U.S. INTO ALBERTA...AND TROUGHING OVER EASTERN CANADA INTO THE NORTHEASTERN U.S.. ALSO OF NOTE WAS A SHORTWAVE OVER SOUTHEAST MONTANA...WHICH WITH A STREAM OF MOISTURE TRANSPORT BRINGING PRECIPITABLE WATER UP TO 1.5-2 INCHES ACROSS MUCH OF THE PLAINS...HAS SUPPORTED SHOWERS AND EMBEDDED THUNDERSTORMS FROM THE DAKOTAS INTO KS. ANOTHER AREA OF SCATTERED SHOWERS AND STORMS WERE PRESENT FROM EASTERN SOUTH DAKOTA INTO SOUTHWEST MN AND WESTERN IA...IN AN AREA OF MID-LEVEL FRONTOGENESIS AND NOSE OF 850MB MOISTURE TRANSPORT. FURTHER TO THE EAST OVER THE FORECAST AREA... HIGH PRESSURE AND DRY AIR DOMINATE. PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGED FROM 1.25 INCHES AT MPX TO 0.44 INCHES AT GRB. SOME HIGHER CLOUDS WERE FLOWING INTO LOCATIONS ALONG/WEST OF THE MISSISSIPPI RIVER...HELPING TO KEEP TEMPERATURES UP THERE. HOWEVER...IN CENTRAL WISCONSIN WHERE THE AIR IS DRIEST AND SKIES ARE MAINLY CLEAR...READINGS HAVE DIPPED INTO THE LOW 40S WITH SOME PATCHY FOG AROUND. THE NORTHWEST FLOW REGIME THE FORECAST AREA SITS IN IS PROGGED TO REMAIN IN PLACE THROUGH TONIGHT. MUCH OF THE FOCUS IS HOW CLOSE THE SHORTWAVE IN SOUTHEAST MONTANA CAN PUSH EAST TOWARDS THE AREA... BEFORE IT GETS CAUGHT UP IN THE NORTHWEST FLOW. MODELS ARE IN GOOD AGREEMENT TRACKING THE SHORTWAVE INTO EASTERN SOUTH DAKOTA BY 12Z SATURDAY. THIS TRACK DOES HELP TO SPREAD HIGHER PRECIPITABLE WATER TOWARDS THE AREA...WITH VALUES INCREASING TO 1.5-1.75 INCHES ALONG AND WEST OF THE MS RIVER FOR TONIGHT. HOWEVER...THE SLOW PROGRESSION OF THE SHORTWAVE...COMBINED WITH THE NOSE OF 850MB MOISTURE TRANSPORT PROGGED TO REMAIN MOSTLY WEST OF I-35 SUGGESTS A VERY LOW PROBABILITY OF ANY PRECIPITATION FOR THE FORECAST AREA. THE 15.00Z NAM...GFS...HIRES-ARW/NMM...NSSL WRF AND ECMWF DEPICT LITTLE IF ANY PRECIPITATION...LEADING TO HIGHER CONFIDENCE OF A DRY FORECAST. REALLY ONLY SMALL PRECIPITATION POTENTIAL WOULD BE... 1. THIS MORNING IN A SECTION OF NORTHEAST IOWA FROM THE PRECIPITATION OFF TO OUR WEST TRYING TO PUSH IN. 2. ALONG THE MS RIVER WHERE THE HRRR/HIRES-ARW/NMM/NSSL WRF ALL DEPICT A WEAK BAND OF SHOWERS OR SPRINKLES. APPEARS TO BE CORRELATED WITH A VERY WEAK SHORTWAVE DROPPING DOWN OUT OF THE DLH AREA. 3. LATE TONIGHT...WEAK ISENTROPIC LIFT MAY BE ABLE TO INITIATE SOME SHOWERS OVER FAR NORTHEAST IA AND SOUTHWEST WISCONSIN...SIMILAR TO THE 15.00Z ECMWF/NSSL WRF-ARW. 925MB TEMPS ARE PROGGED TO BE ABOUT 2C WARMER BY 00Z TODAY COMPARED TO 00Z YESTERDAY...SO WE SHOULD BE ABLE TO TACK ON A FEW DEGREES TO YESTERDAYS HIGHS. HOWEVER...CLOUD COVER MAY HOLD TEMPERATURES BACK SOME...PARTICULARLY ACROSS NORTHEAST IOWA. WITH HIGHER PRECIPITABLE WATER VALUES IN PLACE TONIGHT ALONG WITH SOME CLOUD COVER...MOST LOCATIONS WILL SEE A WARMER NIGHT. EVEN SO...CENTRAL WISCONSIN LOOKS TO CONTINUE TO BE THE COOL SPOT WITH THE DRIEST AIR PRESENT THERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 306 AM CDT FRI AUG 15 2014 THE WEEKEND FORECAST LOOKS TO BE DOMINATED BY TWO FEATURES. FIRST... THE SHORTWAVE TROUGH OVER EASTERN SOUTH DAKOTA AT 12Z SATURDAY... WHICH LOOKS TO UNDER CUT THE FORECAST AREA BY HEADING ROUGHLY THROUGH IOWA ON SUNDAY. SIMILAR TO THE SHORT TERM PERIOD...GIVEN THE SLOW PROGRESSION OF THE SHORTWAVE KEEPING THE DYNAMICS TO THE WEST...AND THE 850MB MOISTURE TRANSPORT NOSE AHEAD OF IT STAYING NEAR OR SOUTH OF I-80...BELIEVE MUCH OF ITS PRECIPITATION SHOULD STAY TO THE SOUTH OF THE FORECAST AREA. WITH THE SHORTWAVE GETTING CLOSER ON SUNDAY...ESPECIALLY IN THE 15.00Z GFS...WILL HAVE TO MAINTAIN SOME LOW CHANCES OF SHOWERS/STORMS WEST OF THE MS RIVER AND SOUTH OF I-90 IN WISCONSIN. THE SECOND FEATURE...A SHORTWAVE TROUGH DROPPING THROUGH ONTARIO ALLOWS A COLD FRONT TO DROP SOUTH THROUGH THE FORECAST AREA LATE SATURDAY THROUGH SATURDAY NIGHT. THIS COLD FRONT...COMBINED WITH DAYTIME HEATING AND SOME MOISTURE PUSHED EAST INTO THE FORECAST AREA...SHOULD BE ENOUGH TO TRIGGER ISOLATED TO MAYBE SCATTERED SHOWERS AND THUNDERSTORMS NORTH OF I-94 SATURDAY AFTERNOON. GIVEN THE NORTHWEST UPPER FLOW AND SOUTHWARD PROGRESSION OF THE FRONT...THESE MAY TRY TO DROP SOUTH THROUGH THE AREA SATURDAY NIGHT...PROVIDED THEY DONT FALL APART WITH LOSS OF DAYTIME INSTABILITY. SATURDAYS HIGHS SHOULD BE CLOSE TO TODAY GIVEN NEARLY IDENTICAL 925MB TEMPS. WITH THE PASSAGE OF THE COLD FRONT SATURDAY NIGHT...925MB TEMPS COOLING ABOUT 3C...POTENTIAL FOR A STRATUS DECK AND A SWITCH TO EASTERLY FLOW...EXPECT COOLER CONDITIONS FOR SUNDAY. ATTENTION EARLY NEXT WEEK THEN TURNS TO THE UPPER LOW OVER THE PACIFIC NORTHWEST. THERE IS SURPRISINGLY GOOD MODEL AGREEMENT FOR THE LOW TO DROP INTO THE FORECAST AREA ON TUESDAY. RETURNING MOISTURE TRANSPORT AHEAD OF THIS UPPER LOW COMBINED WITH DPVA SHOULD YIELD SOME SHOWERS AND THUNDERSTORMS...TRACKING INTO AREAS ALONG/WEST OF THE MISSISSIPPI ON MONDAY AND GRADUALLY ACROSS THE REST OF THE AREA MONDAY NIGHT AND TUESDAY. HAVE CONTINUED TO MENTION 50-60 PERCENT CHANCES. QUICK SOUNDING CHECK WOULD SUGGEST NO SEVERE WEATHER DUE TO WEAK SHEAR. FOR THE MIDDLE OF THE WEEK...THE UPPER LOW GRADUALLY FILLS AND LIFTS NORTHEAST OUT OF THE REGION...IN RESPONSE TO RIDGING BUILDING UP OVER THE PLAINS. STILL NEED TO MAINTAIN SOME LOW CHANCES OF PRECIPITATION ON WEDNESDAY WITH THE UPPER LOW IN THE AREA...AND ALTHOUGH 500MB HEIGHTS RISE GOING INTO THURSDAY...ITS ALSO ACCOMPANIED BY WARM/MOIST AIR ADVECTION. THEREFORE...CHANCES OF SHOWERS AND STORMS CONTINUE INTO THURSDAY. THE WARM ADVECTION WILL BE ENOUGH TOO TO SEND TEMPERATURES ABOVE NORMAL FOR THURSDAY AFTER GENERALLY HOLDING NEAR OR BELOW NORMAL UNTIL THEN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1155 AM CDT FRI AUG 15 2014 INCREASING LOW LEVEL MOISTURE OVER THE NEXT COUPLE DAYS AS HIGH PRESSURE MEANDERS AWAY TO THE SOUTHEAST. LIGHT SFC WIND FIELD...COUPLED WITH RISING TDS...BRINGS THE THREAT FOR SOME FOG INTO THE QUESTION FOR THE OVERNIGHT HOURS. LOOKING SPECIFICALLY AT RIVER VALLEY FOG FOR KLSE...THE DEPTH OF THE LIGHT WIND LAYER IS SHALLOW PER RAP/NAM/GFS BUFKIT SOUNDINGS...GENERALLY LESS THAN 500 FT THROUGH THE NIGHT. PLUS...THE SOUNDINGS ALSO POINT TO SOME WEAK LIFT IN THE LOWER LAYERS ALONG WITH THE POTENTIAL FOR MID/UPPER LEVEL CLOUDINESS ASSOCIATED WITH A TROUGH PASSING TO THE SOUTH. THE INCREASING TDS CERTAINLY FAVOR SOME FUZZ OVERNIGHT...MVFR BR VSBYS. AS FOR THICKER-MORE SIGNIFICANT REDUCTIONS...CAN/T RULE IT OUT...BUT CONFIDENCE SHAKY. IF SKIES ARE MORE CLEAR THAN NOT...AND IF THE DEPTH OF THE LIGHT WIND LAYER INCREASES...LOWER VSBYS WOULD BECOME MORE LIKELY. WORST CASE SCENARIO WOULD BE SUB 1SM BR WITH STRATUS UNDER 1KFT. WILL LIKELY HOLD WITH A MORE OPTIMISTIC OUTCOME FOR NOW...LETTING LATER MODEL RUNS AND TRENDS MOVE THE FORECAST AS NECESSARY. CERTAINLY SOMETHING TO WATCH FOR THROUGH THE NIGHTTIME HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
539 AM CDT FRI AUG 15 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 306 AM CDT FRI AUG 15 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW OVER THE PACIFIC NORTHWEST...RIDGING FROM THE SOUTHWESTERN U.S. INTO ALBERTA...AND TROUGHING OVER EASTERN CANADA INTO THE NORTHEASTERN U.S.. ALSO OF NOTE WAS A SHORTWAVE OVER SOUTHEAST MONTANA...WHICH WITH A STREAM OF MOISTURE TRANSPORT BRINGING PRECIPITABLE WATER UP TO 1.5-2 INCHES ACROSS MUCH OF THE PLAINS...HAS SUPPORTED SHOWERS AND EMBEDDED THUNDERSTORMS FROM THE DAKOTAS INTO KS. ANOTHER AREA OF SCATTERED SHOWERS AND STORMS WERE PRESENT FROM EASTERN SOUTH DAKOTA INTO SOUTHWEST MN AND WESTERN IA...IN AN AREA OF MID-LEVEL FRONTOGENESIS AND NOSE OF 850MB MOISTURE TRANSPORT. FURTHER TO THE EAST OVER THE FORECAST AREA... HIGH PRESSURE AND DRY AIR DOMINATE. PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGED FROM 1.25 INCHES AT MPX TO 0.44 INCHES AT GRB. SOME HIGHER CLOUDS WERE FLOWING INTO LOCATIONS ALONG/WEST OF THE MISSISSIPPI RIVER...HELPING TO KEEP TEMPERATURES UP THERE. HOWEVER...IN CENTRAL WISCONSIN WHERE THE AIR IS DRIEST AND SKIES ARE MAINLY CLEAR...READINGS HAVE DIPPED INTO THE LOW 40S WITH SOME PATCHY FOG AROUND. THE NORTHWEST FLOW REGIME THE FORECAST AREA SITS IN IS PROGGED TO REMAIN IN PLACE THROUGH TONIGHT. MUCH OF THE FOCUS IS HOW CLOSE THE SHORTWAVE IN SOUTHEAST MONTANA CAN PUSH EAST TOWARDS THE AREA... BEFORE IT GETS CAUGHT UP IN THE NORTHWEST FLOW. MODELS ARE IN GOOD AGREEMENT TRACKING THE SHORTWAVE INTO EASTERN SOUTH DAKOTA BY 12Z SATURDAY. THIS TRACK DOES HELP TO SPREAD HIGHER PRECIPITABLE WATER TOWARDS THE AREA...WITH VALUES INCREASING TO 1.5-1.75 INCHES ALONG AND WEST OF THE MS RIVER FOR TONIGHT. HOWEVER...THE SLOW PROGRESSION OF THE SHORTWAVE...COMBINED WITH THE NOSE OF 850MB MOISTURE TRANSPORT PROGGED TO REMAIN MOSTLY WEST OF I-35 SUGGESTS A VERY LOW PROBABILITY OF ANY PRECIPITATION FOR THE FORECAST AREA. THE 15.00Z NAM...GFS...HIRES-ARW/NMM...NSSL WRF AND ECMWF DEPICT LITTLE IF ANY PRECIPITATION...LEADING TO HIGHER CONFIDENCE OF A DRY FORECAST. REALLY ONLY SMALL PRECIPITATION POTENTIAL WOULD BE... 1. THIS MORNING IN A SECTION OF NORTHEAST IOWA FROM THE PRECIPITATION OFF TO OUR WEST TRYING TO PUSH IN. 2. ALONG THE MS RIVER WHERE THE HRRR/HIRES-ARW/NMM/NSSL WRF ALL DEPICT A WEAK BAND OF SHOWERS OR SPRINKLES. APPEARS TO BE CORRELATED WITH A VERY WEAK SHORTWAVE DROPPING DOWN OUT OF THE DLH AREA. 3. LATE TONIGHT...WEAK ISENTROPIC LIFT MAY BE ABLE TO INITIATE SOME SHOWERS OVER FAR NORTHEAST IA AND SOUTHWEST WISCONSIN...SIMILAR TO THE 15.00Z ECMWF/NSSL WRF-ARW. 925MB TEMPS ARE PROGGED TO BE ABOUT 2C WARMER BY 00Z TODAY COMPARED TO 00Z YESTERDAY...SO WE SHOULD BE ABLE TO TACK ON A FEW DEGREES TO YESTERDAYS HIGHS. HOWEVER...CLOUD COVER MAY HOLD TEMPERATURES BACK SOME...PARTICULARLY ACROSS NORTHEAST IOWA. WITH HIGHER PRECIPITABLE WATER VALUES IN PLACE TONIGHT ALONG WITH SOME CLOUD COVER...MOST LOCATIONS WILL SEE A WARMER NIGHT. EVEN SO...CENTRAL WISCONSIN LOOKS TO CONTINUE TO BE THE COOL SPOT WITH THE DRIEST AIR PRESENT THERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 306 AM CDT FRI AUG 15 2014 THE WEEKEND FORECAST LOOKS TO BE DOMINATED BY TWO FEATURES. FIRST... THE SHORTWAVE TROUGH OVER EASTERN SOUTH DAKOTA AT 12Z SATURDAY... WHICH LOOKS TO UNDER CUT THE FORECAST AREA BY HEADING ROUGHLY THROUGH IOWA ON SUNDAY. SIMILAR TO THE SHORT TERM PERIOD...GIVEN THE SLOW PROGRESSION OF THE SHORTWAVE KEEPING THE DYNAMICS TO THE WEST...AND THE 850MB MOISTURE TRANSPORT NOSE AHEAD OF IT STAYING NEAR OR SOUTH OF I-80...BELIEVE MUCH OF ITS PRECIPITATION SHOULD STAY TO THE SOUTH OF THE FORECAST AREA. WITH THE SHORTWAVE GETTING CLOSER ON SUNDAY...ESPECIALLY IN THE 15.00Z GFS...WILL HAVE TO MAINTAIN SOME LOW CHANCES OF SHOWERS/STORMS WEST OF THE MS RIVER AND SOUTH OF I-90 IN WISCONSIN. THE SECOND FEATURE...A SHORTWAVE TROUGH DROPPING THROUGH ONTARIO ALLOWS A COLD FRONT TO DROP SOUTH THROUGH THE FORECAST AREA LATE SATURDAY THROUGH SATURDAY NIGHT. THIS COLD FRONT...COMBINED WITH DAYTIME HEATING AND SOME MOISTURE PUSHED EAST INTO THE FORECAST AREA...SHOULD BE ENOUGH TO TRIGGER ISOLATED TO MAYBE SCATTERED SHOWERS AND THUNDERSTORMS NORTH OF I-94 SATURDAY AFTERNOON. GIVEN THE NORTHWEST UPPER FLOW AND SOUTHWARD PROGRESSION OF THE FRONT...THESE MAY TRY TO DROP SOUTH THROUGH THE AREA SATURDAY NIGHT...PROVIDED THEY DONT FALL APART WITH LOSS OF DAYTIME INSTABILITY. SATURDAYS HIGHS SHOULD BE CLOSE TO TODAY GIVEN NEARLY IDENTICAL 925MB TEMPS. WITH THE PASSAGE OF THE COLD FRONT SATURDAY NIGHT...925MB TEMPS COOLING ABOUT 3C...POTENTIAL FOR A STRATUS DECK AND A SWITCH TO EASTERLY FLOW...EXPECT COOLER CONDITIONS FOR SUNDAY. ATTENTION EARLY NEXT WEEK THEN TURNS TO THE UPPER LOW OVER THE PACIFIC NORTHWEST. THERE IS SURPRISINGLY GOOD MODEL AGREEMENT FOR THE LOW TO DROP INTO THE FORECAST AREA ON TUESDAY. RETURNING MOISTURE TRANSPORT AHEAD OF THIS UPPER LOW COMBINED WITH DPVA SHOULD YIELD SOME SHOWERS AND THUNDERSTORMS...TRACKING INTO AREAS ALONG/WEST OF THE MISSISSIPPI ON MONDAY AND GRADUALLY ACROSS THE REST OF THE AREA MONDAY NIGHT AND TUESDAY. HAVE CONTINUED TO MENTION 50-60 PERCENT CHANCES. QUICK SOUNDING CHECK WOULD SUGGEST NO SEVERE WEATHER DUE TO WEAK SHEAR. FOR THE MIDDLE OF THE WEEK...THE UPPER LOW GRADUALLY FILLS AND LIFTS NORTHEAST OUT OF THE REGION...IN RESPONSE TO RIDGING BUILDING UP OVER THE PLAINS. STILL NEED TO MAINTAIN SOME LOW CHANCES OF PRECIPITATION ON WEDNESDAY WITH THE UPPER LOW IN THE AREA...AND ALTHOUGH 500MB HEIGHTS RISE GOING INTO THURSDAY...ITS ALSO ACCOMPANIED BY WARM/MOIST AIR ADVECTION. THEREFORE...CHANCES OF SHOWERS AND STORMS CONTINUE INTO THURSDAY. THE WARM ADVECTION WILL BE ENOUGH TOO TO SEND TEMPERATURES ABOVE NORMAL FOR THURSDAY AFTER GENERALLY HOLDING NEAR OR BELOW NORMAL UNTIL THEN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 538 AM CDT FRI AUG 15 2014 A WEAK DISTURBANCE WILL SLIDE ACROSS THE REGION TODAY BRINGING SHOWERS AND THUNDERSTORMS TO PORTIONS OF SOUTHERN MINNESOTA INTO CENTRAL/WESTERN IOWA. THIS ACTIVITY SHOULD STAY WEST OF THE TAF SITES WITH VFR CONDITIONS EXPECTED. PLAN ON SOUTH WINDS OF 6 TO 10 KTS TODAY WITH CLOUD BASES RANGING FROM 8 TO 12 KFT. A MOIST AIRMASS SLIDES INTO THE REGION TONIGHT AND WILL CREATE SOME VISIBILITY RESTRICTIONS. PLAN ON 4-5 SM BR AT THE TAF SITES LATE THIS EVENING THROUGH EARLY SATURDAY MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
306 AM CDT FRI AUG 15 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 306 AM CDT FRI AUG 15 2014 CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW OVER THE PACIFIC NORTHWEST...RIDGING FROM THE SOUTHWESTERN U.S. INTO ALBERTA...AND TROUGHING OVER EASTERN CANADA INTO THE NORTHEASTERN U.S.. ALSO OF NOTE WAS A SHORTWAVE OVER SOUTHEAST MONTANA...WHICH WITH A STREAM OF MOISTURE TRANSPORT BRINGING PRECIPITABLE WATER UP TO 1.5-2 INCHES ACROSS MUCH OF THE PLAINS...HAS SUPPORTED SHOWERS AND EMBEDDED THUNDERSTORMS FROM THE DAKOTAS INTO KS. ANOTHER AREA OF SCATTERED SHOWERS AND STORMS WERE PRESENT FROM EASTERN SOUTH DAKOTA INTO SOUTHWEST MN AND WESTERN IA...IN AN AREA OF MID-LEVEL FRONTOGENESIS AND NOSE OF 850MB MOISTURE TRANSPORT. FURTHER TO THE EAST OVER THE FORECAST AREA... HIGH PRESSURE AND DRY AIR DOMINATE. PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS RANGED FROM 1.25 INCHES AT MPX TO 0.44 INCHES AT GRB. SOME HIGHER CLOUDS WERE FLOWING INTO LOCATIONS ALONG/WEST OF THE MISSISSIPPI RIVER...HELPING TO KEEP TEMPERATURES UP THERE. HOWEVER...IN CENTRAL WISCONSIN WHERE THE AIR IS DRIEST AND SKIES ARE MAINLY CLEAR...READINGS HAVE DIPPED INTO THE LOW 40S WITH SOME PATCHY FOG AROUND. THE NORTHWEST FLOW REGIME THE FORECAST AREA SITS IN IS PROGGED TO REMAIN IN PLACE THROUGH TONIGHT. MUCH OF THE FOCUS IS HOW CLOSE THE SHORTWAVE IN SOUTHEAST MONTANA CAN PUSH EAST TOWARDS THE AREA... BEFORE IT GETS CAUGHT UP IN THE NORTHWEST FLOW. MODELS ARE IN GOOD AGREEMENT TRACKING THE SHORTWAVE INTO EASTERN SOUTH DAKOTA BY 12Z SATURDAY. THIS TRACK DOES HELP TO SPREAD HIGHER PRECIPITABLE WATER TOWARDS THE AREA...WITH VALUES INCREASING TO 1.5-1.75 INCHES ALONG AND WEST OF THE MS RIVER FOR TONIGHT. HOWEVER...THE SLOW PROGRESSION OF THE SHORTWAVE...COMBINED WITH THE NOSE OF 850MB MOISTURE TRANSPORT PROGGED TO REMAIN MOSTLY WEST OF I-35 SUGGESTS A VERY LOW PROBABILITY OF ANY PRECIPITATION FOR THE FORECAST AREA. THE 15.00Z NAM...GFS...HIRES-ARW/NMM...NSSL WRF AND ECMWF DEPICT LITTLE IF ANY PRECIPITATION...LEADING TO HIGHER CONFIDENCE OF A DRY FORECAST. REALLY ONLY SMALL PRECIPITATION POTENTIAL WOULD BE... 1. THIS MORNING IN A SECTION OF NORTHEAST IOWA FROM THE PRECIPITATION OFF TO OUR WEST TRYING TO PUSH IN. 2. ALONG THE MS RIVER WHERE THE HRRR/HIRES-ARW/NMM/NSSL WRF ALL DEPICT A WEAK BAND OF SHOWERS OR SPRINKLES. APPEARS TO BE CORRELATED WITH A VERY WEAK SHORTWAVE DROPPING DOWN OUT OF THE DLH AREA. 3. LATE TONIGHT...WEAK ISENTROPIC LIFT MAY BE ABLE TO INITIATE SOME SHOWERS OVER FAR NORTHEAST IA AND SOUTHWEST WISCONSIN...SIMILAR TO THE 15.00Z ECMWF/NSSL WRF-ARW. 925MB TEMPS ARE PROGGED TO BE ABOUT 2C WARMER BY 00Z TODAY COMPARED TO 00Z YESTERDAY...SO WE SHOULD BE ABLE TO TACK ON A FEW DEGREES TO YESTERDAYS HIGHS. HOWEVER...CLOUD COVER MAY HOLD TEMPERATURES BACK SOME...PARTICULARLY ACROSS NORTHEAST IOWA. WITH HIGHER PRECIPITABLE WATER VALUES IN PLACE TONIGHT ALONG WITH SOME CLOUD COVER...MOST LOCATIONS WILL SEE A WARMER NIGHT. EVEN SO...CENTRAL WISCONSIN LOOKS TO CONTINUE TO BE THE COOL SPOT WITH THE DRIEST AIR PRESENT THERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 306 AM CDT FRI AUG 15 2014 THE WEEKEND FORECAST LOOKS TO BE DOMINATED BY TWO FEATURES. FIRST... THE SHORTWAVE TROUGH OVER EASTERN SOUTH DAKOTA AT 12Z SATURDAY... WHICH LOOKS TO UNDER CUT THE FORECAST AREA BY HEADING ROUGHLY THROUGH IOWA ON SUNDAY. SIMILAR TO THE SHORT TERM PERIOD...GIVEN THE SLOW PROGRESSION OF THE SHORTWAVE KEEPING THE DYNAMICS TO THE WEST...AND THE 850MB MOISTURE TRANSPORT NOSE AHEAD OF IT STAYING NEAR OR SOUTH OF I-80...BELIEVE MUCH OF ITS PRECIPITATION SHOULD STAY TO THE SOUTH OF THE FORECAST AREA. WITH THE SHORTWAVE GETTING CLOSER ON SUNDAY...ESPECIALLY IN THE 15.00Z GFS...WILL HAVE TO MAINTAIN SOME LOW CHANCES OF SHOWERS/STORMS WEST OF THE MS RIVER AND SOUTH OF I-90 IN WISCONSIN. THE SECOND FEATURE...A SHORTWAVE TROUGH DROPPING THROUGH ONTARIO ALLOWS A COLD FRONT TO DROP SOUTH THROUGH THE FORECAST AREA LATE SATURDAY THROUGH SATURDAY NIGHT. THIS COLD FRONT...COMBINED WITH DAYTIME HEATING AND SOME MOISTURE PUSHED EAST INTO THE FORECAST AREA...SHOULD BE ENOUGH TO TRIGGER ISOLATED TO MAYBE SCATTERED SHOWERS AND THUNDERSTORMS NORTH OF I-94 SATURDAY AFTERNOON. GIVEN THE NORTHWEST UPPER FLOW AND SOUTHWARD PROGRESSION OF THE FRONT...THESE MAY TRY TO DROP SOUTH THROUGH THE AREA SATURDAY NIGHT...PROVIDED THEY DONT FALL APART WITH LOSS OF DAYTIME INSTABILITY. SATURDAYS HIGHS SHOULD BE CLOSE TO TODAY GIVEN NEARLY IDENTICAL 925MB TEMPS. WITH THE PASSAGE OF THE COLD FRONT SATURDAY NIGHT...925MB TEMPS COOLING ABOUT 3C...POTENTIAL FOR A STRATUS DECK AND A SWITCH TO EASTERLY FLOW...EXPECT COOLER CONDITIONS FOR SUNDAY. ATTENTION EARLY NEXT WEEK THEN TURNS TO THE UPPER LOW OVER THE PACIFIC NORTHWEST. THERE IS SURPRISINGLY GOOD MODEL AGREEMENT FOR THE LOW TO DROP INTO THE FORECAST AREA ON TUESDAY. RETURNING MOISTURE TRANSPORT AHEAD OF THIS UPPER LOW COMBINED WITH DPVA SHOULD YIELD SOME SHOWERS AND THUNDERSTORMS...TRACKING INTO AREAS ALONG/WEST OF THE MISSISSIPPI ON MONDAY AND GRADUALLY ACROSS THE REST OF THE AREA MONDAY NIGHT AND TUESDAY. HAVE CONTINUED TO MENTION 50-60 PERCENT CHANCES. QUICK SOUNDING CHECK WOULD SUGGEST NO SEVERE WEATHER DUE TO WEAK SHEAR. FOR THE MIDDLE OF THE WEEK...THE UPPER LOW GRADUALLY FILLS AND LIFTS NORTHEAST OUT OF THE REGION...IN RESPONSE TO RIDGING BUILDING UP OVER THE PLAINS. STILL NEED TO MAINTAIN SOME LOW CHANCES OF PRECIPITATION ON WEDNESDAY WITH THE UPPER LOW IN THE AREA...AND ALTHOUGH 500MB HEIGHTS RISE GOING INTO THURSDAY...ITS ALSO ACCOMPANIED BY WARM/MOIST AIR ADVECTION. THEREFORE...CHANCES OF SHOWERS AND STORMS CONTINUE INTO THURSDAY. THE WARM ADVECTION WILL BE ENOUGH TOO TO SEND TEMPERATURES ABOVE NORMAL FOR THURSDAY AFTER GENERALLY HOLDING NEAR OR BELOW NORMAL UNTIL THEN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1143 PM CDT THU AUG 14 2014 THE LARGE AREA OF HIGH PRESSURE REMAINS NEAR THE SOUTHERN TIP OF LAKE MICHIGAN THIS EVENING. THE HIGH WILL CONTINUE TO SLOWLY SLIDE OFF TO THE SOUTHEAST THROUGH THE PERIOD AS WEAK SHORT WAVE TROUGHS MOVE OVER THE REGION. ONE OF THESE SHORT WAVE TROUGHS WAS OVER SOUTH DAKOTA WHERE SCATTERED SHOWERS AND STORMS WERE OCCURRING. THE 15.00Z NAM CONTINUES TO SHOW THIS WAVE MOVING BY WEST OF THE AREA LATE TONIGHT INTO FRIDAY MORNING WITH THE SHOWERS ALSO STAYING WEST OF THE AREA. EARLIER RUNS OF THE HRRR SUGGESTED SOME OF THESE SHOWERS COULD POSSIBLY GET INTO THE AREA BUT SUBSEQUENT RUNS THIS EVENING...WITH THE 15.03Z BEING THE LATEST...ALL SHOW THIS STAYING WEST OF THE AREA SIMILAR TO THE NAM. ADDITIONAL ACTIVITY SHOULD DEVELOP FRIDAY WITH THIS SHORT WAVE TROUGH...BUT BY THEN IT SHOULD BE FAR ENOUGH SOUTH THAT IT WILL NOT IMPACT EITHER TAF. THEREFORE...EXPECTING VFR CONDITIONS THROUGH THE PERIOD WITH A MID LEVEL CEILING MOVING IN LATE TONIGHT OR FRIDAY MORNING WITH THE PASSAGE OF THE SHORT WAVE TROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CDT THU AUG 14 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 236 PM CDT THU AUG 14 2014 AT 3 PM...WHILE A 1020 MB HIGH PRESSURE IS PROVIDING PARTLY TO MOSTLY SUNNY SKIES ACROSS THE LOCAL AREA...MODERATE TO STRONG 900 TO 500 MB FRONTOGENESIS IS PRODUCING A BAND OF SHOWERS AND THUNDERSTORMS ACROSS EASTERN SOUTH DAKOTA AND NORTHWEST IOWA. THE 14.12Z DETERMINISTIC AND MESO MODELS SHOW THAT THE 900 TO 500 MB FRONTOGENETIC FORCING AND MODERATE TO STRONG 310K ISENTROPIC LIFT WILL SLOWLY EAST ACROSS SOUTHWEST MINNESOTA AND WESTERN IOWA TONIGHT...AND INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON FRIDAY. THIS IS SLIGHTLY SLOWER THAN PREVIOUS MODEL SOLUTIONS...SO KEPT OUR AREA DRY TONIGHT AND THEN KEPT THE RAIN CHANCES IN THE 20 TO 40 PERCENT RANGE MAINLY WEST OF THE MISSISSIPPI RIVER ON FRIDAY. HOWEVER AM A BIT CONCERNED THAT WITH THE WESTWARD TREND IN THE MODELS AND DRY LOW LEVELS THAT THESE PRECIPITATION CHANCES MAY HAVE TO BE SHIFTED A BIT FURTHER WEST. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 236 PM CDT THU AUG 14 2014 ON FRIDAY NIGHT AND SATURDAY...THE MODELS CONTINUE TO SHOW THAT A WEAKENING BACKDOOR DOOR COLD FRONT WILL MOVE SOUTH ACROSS WISCONSIN...AND THE FRONTOGENETIC FORCING TO OUR SOUTH WILL SLOWLY SHIFT SOUTH AND WEST AS A LOW PRESSURE SYSTEM MOVES SOUTHEAST OUT OF SOUTH DAKOTA. DEPENDING ON HOW THIS EVOLVES...WE MAY END UP WITH THE BEST CHANCES OF SHOWERS AND STORMS ALONG AND NORTH OF INTERSTATE 94...AND ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. ELSEWHERE THERE IS A POSSIBILITY THAT THESE AREAS MAY GET MISSED BY THE PRECIPITATION. THIS IS DUE TO THE SUBSIDENCE BETWEEN THESE TWO SYSTEMS. THE 14.18Z NAM JUST CAME IN AND IT SHOWS THAT THE 310K ISENTROPIC LIFT AND MOISTURE TRANSPORT IS MUCH FURTHER SOUTHWEST...SO THERE ARE QUESTIONS ON WHETHER THE PRECIPITATION CHANCES IN OUR SOUTH AND WEST MAY BE TOO HIGH. ON SATURDAY NIGHT AND SUNDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST ACROSS IOWA. AS THIS LOW MOVES INTO SOUTHEAST IOWA...DRIER AIR WILL ADVECT INTO THE AREA FROM THE NORTHEAST. BOTH THE GFS AND ECMWF ARE SHOWING THIS WELL IN THEIR SURFACE DEW POINTS. MEANWHILE THE NAM IS HOLDING ONTO THE MID AND UPPER 60 DEW POINTS. SINCE THE NAM IS TYPICALLY TOO HIGH WITH ITS DEW POINTS IN THESE SITUATIONS...PREFER THE DRIER GFS AND ECMWF SOLUTIONS. FROM MONDAY NIGHT INTO WEDNESDAY...THERE CONTINUES TO BE SOME GOOD CONSISTENCY THAT A TROUGH OR CLOSED LOW WILL MOVE SLOWLY EAST THROUGH THE AREA. THE MODEL CONSENSUS ALREADY HAS FAIRLY HIGH /40 TO 60 PERCENT/ PRECIPITATION CHANCES FOR THIS TIME PERIOD...SO MADE NO CHANGES TO IT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1143 PM CDT THU AUG 14 2014 THE LARGE AREA OF HIGH PRESSURE REMAINS NEAR THE SOUTHERN TIP OF LAKE MICHIGAN THIS EVENING. THE HIGH WILL CONTINUE TO SLOWLY SLIDE OFF TO THE SOUTHEAST THROUGH THE PERIOD AS WEAK SHORT WAVE TROUGHS MOVE OVER THE REGION. ONE OF THESE SHORT WAVE TROUGHS WAS OVER SOUTH DAKOTA WHERE SCATTERED SHOWERS AND STORMS WERE OCCURRING. THE 15.00Z NAM CONTINUES TO SHOW THIS WAVE MOVING BY WEST OF THE AREA LATE TONIGHT INTO FRIDAY MORNING WITH THE SHOWERS ALSO STAYING WEST OF THE AREA. EARLIER RUNS OF THE HRRR SUGGESTED SOME OF THESE SHOWERS COULD POSSIBLY GET INTO THE AREA BUT SUBSEQUENT RUNS THIS EVENING...WITH THE 15.03Z BEING THE LATEST...ALL SHOW THIS STAYING WEST OF THE AREA SIMILAR TO THE NAM. ADDITIONAL ACTIVITY SHOULD DEVELOP FRIDAY WITH THIS SHORT WAVE TROUGH...BUT BY THEN IT SHOULD BE FAR ENOUGH SOUTH THAT IT WILL NOT IMPACT EITHER TAF. THEREFORE...EXPECTING VFR CONDITIONS THROUGH THE PERIOD WITH A MID LEVEL CEILING MOVING IN LATE TONIGHT OR FRIDAY MORNING WITH THE PASSAGE OF THE SHORT WAVE TROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
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
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 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 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 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...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 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
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 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
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 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
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 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 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
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 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
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 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 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 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 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 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
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 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
  [top] 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 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 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 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 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 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
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 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 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 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 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 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 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 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