Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/15/19

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
552 PM MDT Wed Aug 14 2019 .AVIATION... 00Z TAF CYCLE Showers and thunderstorms will continue to shift E-SE through the evening, potentially impacting KTCC and KROW over the next several hours before diminishing. Localized MVFR conditions in heavy rain will be possible. Small hail and gusty outflow winds are also possible. Current outflow boundary collisions near KAEG and KABQ have not produced additional thunderstorms, thus the window for storms at these locations is closing. The few showers and thunderstorms persisting across the west will diminish by sunset. On Thursday, though a few storms will be possible across northern NM, the focus should be across the high terrain south of I-40. 34 && .PREV DISCUSSION...320 PM MDT Wed Aug 14 2019... .SYNOPSIS... Storms stretching from the Continental Divide to the central mountain chain this afternoon will continue to track into the eastern plains this evening, where a few could become strong to severe with large hail and damaging winds. Thunderstorm coverage trends downward Thursday and Friday as temperatures warm a little across much of the state. Even drier conditions expected for the weekend when portions of the east central and southeast may experience near record highs. Storms could return to northern and central New Mexico early next week. && .DISCUSSION... Drier air continues to reside over portions of northwest New Mexico, while the boundary that pushed to the Continental Divide was the focus for storm development this morning and early this afternoon. With the upper high centered over western NM/eastern AZ, storms will be moving to the east and southeast. Expect that the majority of the current activity will be focused along and south of I-40 and along and east of I-25 later this afternoon and early this evening, propagating into the eastern plains, where a few strong to severe storms with large hail and damaging winds are possible. Both the RAP13 and HRRR hold onto some precipitation after midnight over the eastern plains, but the RAP13 has much more lingering after midnight over the west central and southwest, so will have to monitor for this potential. Drier air is still expected to make additional progress over northern and central NM Thursday and Friday, as the flow aloft trends more westerly. Storms will favor the southern high terrain where moisture will be tougher to sweep out. High temperatures will warm a few degrees and overnight lows over some of the northwest and north central should be a bit cooler. The weekend appears even drier with a dearth of storms. The southwest mountains would be the most likely place to see a few storms. There could be some near record to record highs over the east central and southeast, with Roswell on track to experience several days in a row of 100 degree plus temperatures, topping out on Sunday at 105. The upper air pattern changes early next week, reverting to a ridge centered over NM. Some moisture may seep back into the region, and high temperatures may cool a few degrees over the eastern plains as the the GFS drifts the center of circulation towards CO by next Tuesday. The ECMWF positions the high center over AZ by the middle of next week. Either way, monsoon storms will likely remain fewer in number for mid August. && .FIRE WEATHER... Hot, dry and unstable conditions prevail today across far northwest New Mexico, but a backdoor front pushed west to the Continental Divide this morning and brought added moisture and cooler temperatures to central and eastern portions of the state. The added moisture is resulting in a round of wetting storms, which will impact much of central and northeast New Mexico this afternoon and evening. Otherwise, a warming and drying trend is forecast for at least the northern half of the state over the next several days as the westerlies penetrate further east. This will result in an expansion of hot, dry and unstable conditions through at least Sunday as the upper high sets up south of the state. The upper high is forecast to move to near the Four Corners or southern Colorado next week, which may allow moisture to come up from the south and result in the return of chances for wetting storms. Until then, expect above to well above normal temperatures and worsening humidity recovery. 11 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
852 PM CDT Wed Aug 14 2019 .UPDATE... Issued at 849 PM CDT Wed Aug 14 2019 Overall the forecast is working out okay, but did make a few tweaks to PoPs based on latest HRRR output. The rest of the forecast elements look okay. && .SHORT TERM...(This Evening through Thursday Night) Issued at 335 PM CDT Wed Aug 14 2019 Surface heating cu across the region under surface high pressure will dissipate into the evening hours. Otherwise, expect mostly clear skies tonight with some waa/mid level accas storms possible mainly late tonight out west in advance of an approaching short wave trough. There also may be some patchy fog in the east later tonight. On Thursday, the ops models and high-res models all show better/more numerous storm development on Thursday afternoon into the evening with lift from a short wave trough and surface front moving in. Cloud cover and morning storms could affect the build up of instability for storms in the afternoon and evening. At this time, expect there to be plenty of mucape/instability along with good deep layer shear from 35 to 50 knots. Therefore, expect storms to develop with some being supercells/possibly severe as they move southeast with the associated upper trough and surface cold front. Have in the best chances of storms in the afternoon/early evening across the cwa. The severe weather slight risk area had been expanded across most of the cwa for this time. The storms will leave the eastern cwa Thursday night with cooler and drier north winds in behind them. .LONG TERM...(Friday through Wednesday) Issued at 335 PM CDT Wed Aug 14 2019 Progressive zonal to northwesterly flow will continue at 500mb through Sunday night. A few disturbances rolling trough will help trigger wet weather. Friday afternoon and evening will have the highest chance of showers and thunderstorms over our southern counties, with most of the activity being across NE. The focus will then shift to our eastern counties Saturday morning through Sunday night. 850mb temperatures will briefly fall to 10-13C again Saturday afternoon and evening. Depending on cloud cover, we may need to cut back on the upper 70s surface temperatures currently forecast for Saturday afternoon. The cool down will likely be short lived 850mb temperatures rebound to 16 to 22C Sunday afternoon, at least off the 12Z GFS. Just how quickly we return to southerly flow will impact our temperatures Sunday. NBM looks a little slow/cooler than some of the operational models to bring back the warmer air, and there is plenty of uncertainty. It`s more likely that we will return to temperatures that are more typical for this time of year on Monday. This is when the 500mb high across the south central U.S. pushes a ridge across South Dakota and west central MN through much of the rest of the long term period. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) Issued at 641 PM CDT Wed Aug 14 2019 VFR skies/vsbys are expected through tonight, although there could be patchy fog toward morning. Not confident enough to include in forecast at this time. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TDK SHORT TERM...Mohr LONG TERM...KF AVIATION...TDK
Area Forecast Discussion
National Weather Service Denver/Boulder CO
830 PM MDT Wed Aug 14 2019 .UPDATE... Issued at 830 PM MDT Wed Aug 14 2019 The airmass on the plains remained to stable to support any afternoon convection and the main storm ended up being a lone supercell moving southward from Yuma County. A few more weak showers tried to develop over northern Weld County, but they are now ingesting the cool and stable air left over from the earlier shower activity. As the outflow reaches the foothills, the airmass is expected to remain too stable for any nocturnal convection to develop. Skei sshould remain mostly clear. High resolution models do not advertise any fog or low clouds as winds are expected to become drainage southerlies which keep the low levels dry overnight. The forecast has been updated for the canellation of the Severe Thunderstorm Watch and to remove the mention of thunderstorms overnight. && .SHORT TERM...(This evening through Thursday) Issued at 329 PM MDT Wed Aug 14 2019 Current GOES-16 data and surface observations show the surface boundary, separating much more moist low-level air from a bit drier air to the west, across the far northeast corner of Colorado. Dewpoints are still in the low 60s with ESE winds east of the boundary, while west of the boundary dewpoints are in the mid to upper 50s with SW winds. We don`t expect the boundary to light up this afternoon in Colorado, it`s not a sharp gradient and it is fighting mid-level subsidence from the departing short wave trough. However, convection is expected to initiate in Wyoming and then roll off the Cheyenne Ridge 4 PM or so. Storm coverage will be minimal, as we expect any storms to form to be isolated, perhaps just a couple of them. MLCAPE and shear profiles are enough for supercells, with the main threat giant hail and possibly a tornado. They should move ESE across northeast Colorado, generally east of a line from Cheyenne to Fort Morgan to Burlington. Elsewhere, instability is limited, and shear a bit weaker. Weak convection is occurring across the Palmer Divide presently, and this activity should move off to the east across Lincoln County. Severe weather potential is more limited to the south but lightning and marginally severe hail are possible, especially as they move into Lincoln County. Storm chances are very low for the I-25 urban corridor and the high country, especially west of the Continental Divide. Convective activity should wind down across our area after 11 PM. The chance of a repeat of last night`s convection along I-25 is much lower than last night. Instability is less, there is mid- level subsidence, and the strength of the gust front should be less given the expected isolated nature of the storms this afternoon/evening. Still, can`t rule it out so will preserve 10-20% PoPs east of the foothills through midnight. Clearing skies and lows in the 50s across the plains, and around 60 in the urban heat islands. Mountains should cool into the 40s. On Thursday, weak WNW flow continues across Colorado with a dominant sub-tropical ridge over the desert southwest. PW values drop to 0.5" across the front range in the dry WNW flow, but still 1.0" across the far eastern plains. A moisture gradient will set up again across the far eastern plains and thus there is a slight chance of thunderstorms for the far northeast corner. Any storms that manage to develop could be severe with large hail. Elsewhere, convective chances are low. Just a slight chance of a weak thunderstorm across the Palmer Divide. 700 mb temperatures warm a few degC, so highs should be 90-95 across the plains, especially given even less afternoon cloud cover. Expect 70s to low 80s in the high country, with 50s above treeline. .LONG TERM...(Thursday night through Wednesday) Issued at 329 PM MDT Wed Aug 14 2019 There will be a few more weak shortwaves moving over the northern Rockies through Saturday, then the upper ridge will build northward over Colorado. Dry and hot air aloft will be moving over from the west, but there will still be some low level moisture over the plains on Friday. Models have had pretty good agreement on a shallow surge of moist and possibly cooler air over the plains, but they disagree on the strength of this. The NAM actually keeps temperatures in the 70s near the eastern border Friday afternoon, which looks overdone. There will likely be some stratus that could hold on long enough to impact the temperatures by a few degrees though, which in turn could restrain convection. Moisture should mix out pretty well further west, so if there are any storms they should be on the dry/windy side. Still a threat of severe storms over the eastern plains if/when it gets warm enough late in the day. Saturday looks like a transition day as the ridge builds. The westerly flow aloft should bring continued drying, but there may still be enough moisture left, and a little lift from the last effective shortwave passing north of us, for some isolated convection. The combination of heat/dry/breezy/isolated storms raises fire weather concerns for Friday and Saturday--see below for more on that. For Sunday into next week, the ridge will be overhead with hot dry air. The models are still producing some convection to create mid/high clouds each afternoon, but not any precipitation. This could restrain highs a little, but only if it develops early enough in the day. We nudged highs a couple of degrees warmer than the model blends for Sunday and Monday, with highs in the mid to upper 90s on the plains which will be near the records for those days. The trend in the models is toward holding the ridge stronger over the central Rockies or shifting it a bit further west which would shield us from much moisture import through the week. There will still likely be a gradual northward creep of moisture, enough for some late day storms mainly over the mountains, but maybe not much in the way of rain or cooling if the latest trends turn out to be correct. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 830 PM MDT Wed Aug 14 2019 The outflow boundary from this evening`s convection over the far northeast plains will be reaching KDEN before 9 PM with easterly gusts up to about 25 knots. Although dew points will be rising with the arrival of the outflow boundary, the HRRR model shows the winds turning to drainage southerlies by 11 PM and no fog is expected. Winds are expected to become westerly through the day tomorrow, so the only aviation impacts should be the gusty winds between 845 and 10 PM. && .FIRE WEATHER... Issued at 329 PM MDT Wed Aug 14 2019 Hot temperatures and moderate westerly flow aloft will combine with low humidities to create conditions near Red Flag criteria over the mountain valleys and foothills on Friday and Saturday afternoons, with minimum humidities around 15% and wind gusts in the 20-30 mph range. At this point, the worst conditions are expected Friday afternoon. Fuels will continue to dry and may be dry enough for rapid fire growth in the areas that have received less rain over the last month. Hot and dry conditions will continue into next week, but winds will be lighter. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Dankers SHORT TERM...Schlatter LONG TERM...Gimmestad AVIATION...Dankers FIRE WEATHER...Gimmestad
Area Forecast Discussion
National Weather Service Caribou ME
1043 PM EDT Wed Aug 14 2019 .SYNOPSIS... High pressure in Ontario will slowly build toward the region through tonight. The high will settle into Maine Thursday before moving east Friday. A southwest flow will develop across the area over the weekend and into Monday. && .NEAR TERM /THROUGH THURSDAY/... 1025 PM Update...Clouds continue to hang on per the latest satl loops showing some clouds extending from NE Maine down into SW Maine. Most of the cloudiness was sct-bkn w/bases at 7k ft. 00Z UA showed a trof axis across the region w/some moisture showing up around 850 mbs. This trof was aiding the clouds. The last few runs of the RAP showed the clouds starting to break up after 06z as some high pres ridging takes hold. Temps were adjusted to match to the current obs. Overnight forecast lows look w/in the ballpark attm. Previous Discussion... High pressure will be moving across the region overnight into Thursday. Patchy fog around lakes and rivers early morning then lifting then scattered cumulus clouds building. Not as cool tonight with lows in the lower 50s. Pleasant tomorrow with highs in the low 70s north, mid 70s central and southern portions of the forecast area. Loaded a blend of the GFS/NAM/ECMWF/GEM to smooth out the minor differences in the models. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... A low will track into the state early in the period, bringing rain to the area. The low will track from SW to NE Maine and exit the area early Saturday morning, higher pressure will briefly build into the area ahead of another system. Early Sunday morning a warm front pushes into western Maine border with Quebec, by morning it will move into central Maine bringing another round of showers to the area. By the end of period Sunday evening it will exit the region into New Brunswick. Loaded a blend of the GFS/NAM/ECMWF/GEM to smooth out the minor differences in the models. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Upper level westerly flow will be over the region Sunday through Wednesday. Will be difficult to time shortwaves this far out in this pattern, but there appears to be a chance of precipitation most days. Warm and muggy as well especially Sunday and Monday, which also appear to be the days with the best shot at showers and storms at this point. Most models have slightly drier air moving in Tuesday and Wednesday behind a weak cold front with temperatures dropping from above average to near average. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR conditions through the period, patchy morning fog in and around lakes and rivers. The fog will lift by mid morning then sct cu will develop. SHORT TERM: Thursday evening through Monday... VFR conditions early, falling to MVFR in showers for FVE, CAR, PQI, and HUL as a low pressure system tracks across the northern half of the state. The low will clear the area early Saturday morning and higher pressure will briefly build in. Saturday Morning...MVFR conditions will remain across northern Maine until the next system moves into central Maine. Northern sites will fall to Low MVFR to IFR conditions in showers. These conditions will spread to BHB and BGR Saturday evening. Monday morning...This system will clear the area, VFR conditons will return to all sites. Patchy fog near rivers and lakes during the early morning hours, otherwise VFR through the end of the period. && .MARINE... NEAR TERM: Winds and seas below Small Craft Advisory levels through the period. SHORT TERM: Winds and seas below Small Craft Advisory levels through the period. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Hewitt
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
601 PM MDT Wed Aug 14 2019 .UPDATE... Issued at 549 PM MDT Wed Aug 14 2019 Please see updated 00Z aviation discussion below. && .SHORT TERM...(This evening through Friday) Issued at 240 PM MDT Wed Aug 14 2019 Short term concerns will be on convective potential and coverage through Friday. Right now quiet over the CWA as inhibition and lack of any forcing has prevented all but a few brief showers around the mtns so far. HRRR/NAM remaining quite sparse on activity the rest of this afternoon into this evening with just a few indications near the Colorado border over the next few hours. A somewhat better chance for some strong storms looks to occur later tonight over far northern parts of the CWA as a shortwave clips that area but latest HRRR has also backed off on that activity. Not much change seen for Thursday with best chances for convection over northern parts of the CWA in the afternoon with another weak impulse passing by. Sfc boundary will be banked up against the mtns Thursday through Friday keeping temperature over the plains on the mild side for this time of year. Modest upslope flow will keep chances for convection going through Friday. .LONG TERM...(Friday night through Wednesday) Issued at 240 PM MDT Wed Aug 14 2019 A drier pattern looks to set up over the area this weekend into early next week as the westerlies lift northward and upper ridging strengthens over the area. A mostly westerly upper flow will be over the region with moisture limited so only isolated late day showers and storms seen, mainly Weds. Turning warmer Sunday with quite warm conditions remaining into early next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 549 PM MDT Wed Aug 14 2019 Conditional aviation impacts possible this evening and partially overnight with isolated/scattered TSRA near KCDR/KAIA 06-09Z tonight. Isolated -SHRA will also be possible near KCYS through 03Z tonight. Some Hi-res models indicate the TSRA possible near KCDR/KAIA could be farther east in central Nebraska. The next aviation impact will be patchy fog and low ceilings in the Nebraska Panhandle with highest confidence near KBFF/KAIA/KSNY from 10-15Z Thursday morning. Thereafter, VFR conditions are expected through the day. Surface winds will be southeasterly for the Nebraska Plains and west in the high terrain at 10 to 15 knots overnight and then increasing again Thursday afternoon with gusts upwards of 20 to 25 knots. && .FIRE WEATHER... Issued at 240 PM MDT Wed Aug 14 2019 Overall Fire weather concerns look to remain on the low side with fuels still mostly non-critical. Exceptions will continue to be over southwestern Carbon county where winds and low afternoon humidity will continue to produce near critical to critical conditions again Thursday. Otherwise widely scattered showers and storms will move over parts of the area at times tonight through Saturday before drier conditions settle in Sunday into early next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning until 8 PM MDT this evening for WYZ304. Fire Weather Watch from Thursday afternoon through Thursday evening for WYZ304. NE...None. && $$ UPDATE...JSA SHORT TERM...RE LONG TERM...RE AVIATION...JSA FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1050 PM CDT Wed Aug 14 2019 .UPDATE... New storms have developed along the gust front south of I-10. Cells are showing signs of weakening as the cold pool is starting to move away from the convection. Have adjusted POPs to show rain chances farther south. We have also removed POPs overnight. Short term models show this as the last round. && .PREV DISCUSSION... /ISSUED 857 PM CDT Wed Aug 14 2019/ UPDATE... A second line of showers and thunderstorms is moving through the eastern part of the CWA. This line will continue for another hour or two. We are starting to see the outflow becoming dominant which suggests the storms losing energy. Convection has ended out west. We have adjusted the POPs for the rest of the evening to reflect these developments. We have also made some adjustment to the POPs for Thursday. With the convection we`ve had today, chances for development seem less likely Thursday, so we have reduced POPs across the area. It sill looks like there will be a slight chance across the north and east with a bit higher chance over the southeast. But, most places will probably be dry. PREV DISCUSSION... /ISSUED 640 PM CDT Wed Aug 14 2019/ UPDATE... A broken line of showers and thunderstorms is moving southward through our CWA. This line stretches from Blanco to Del Rio. It has been slowly weakening as it moves south and this trend should continue as the sun sets and the convection pushes more stable air ahead of it. We have adjusted the POPs in the short term to reflect this situation, increasing them a little farther south and decreasing them behind the line. Some places have had significant cooling with rain: Fredericksburg dropped to 77 degrees after a rain shower. It might be hard to keep up with hourly temperatures where there is rain cooled air. But temperatures should rebound once warmer air mixes back in. PREV DISCUSSION... /ISSUED 627 PM CDT Wed Aug 14 2019/ AVIATION /00Z TAFs/... VFR conditions are expected to prevail through the TAF period, save for temporary drops to MVFR should TSRA impact DRT through sunset. A series of southward-sagging outflow boundaries and stationary front bisecting Central Texas will continue to serve as foci for TSRA development through early evening before loss of heating allows for convection to wane. Have removed VCSH mention from SAT/SSF as current motion keeps outflow north and west of the San Antonio terminals until closer to 04-06Z and will handle any lingering TSRA/SHRA with amendments if needed. Outflow has cleared DRT this evening and with visible satellite showing new updrafts forming behind it have added a TEMPO TSRA mention for DRT through 01Z. 20-30 knot gusts will be possible in the vicinity of TSRA. Otherwise, outflow approaching AUS may result in isolated SHRA development near the terminal and a northerly wind shift between 01-02Z. Light and variable winds are expected overnight in the presence of these boundaries with heating resulting in a secondary round of SHRA/TSRA development late in the TAF period as convective temperatures are reached. Have introduced VCSH starting 18-20Z for all South Central Texas terminals for Thursday afternoon with additional refinements to timing likely as boundary positions become better defined during the day Thursday. PREV DISCUSSION... /ISSUED 230 PM CDT Wed Aug 14 2019/ SHORT TERM (Tonight through Thursday Night)... Weak boundary north of the region has had just enough low level convergence to get showers and thunderstorms going this afternoon aided by daytime heating. Scattered rain chances this afternoon and evening are for areas west of I-35 and north of US-90. Rain chances linger into tomorrow in association with the passage of this boundary. As a result, temperatures should be a couple degrees below what they have been earlier in the week for most of the area. However, eastern areas will still be near heat advisory criteria. Forecast soundings from Del Rio and Austin tomorrow afternoon show an inverted V pattern in the lower levels with elevated DCAPE values near 1500 J/Kg. If a thunderstorm or two were to get going tomorrow, the biggest threat will be strong winds. There is model disagreement for tomorrow`s possible activity with the ECMWF keeping the region mostly dry, GFS and NAM are more robust with the convection. Latest runs of the NMMB and HRRR also suggest scattered convective activity Thursday. Not anticipating much in the way of accumulation, most areas will be lucky if they get a tenth of an inch, isolated amounts could be higher. LONG TERM (Friday through Wednesday)... By Friday the forecast enters another dry and warming trend as the subtropical high continues to remain anchored over the state. Temperatures will climb back to the century mark for most places and heat advisory criteria will likely be met for our eastern counties with heat index values forecasted to be 108-110 early next week. Near the end of the period, a weakness in the ridge develops east of the Mississippi River Valley and may allow disturbances to ride around the edge of the high as it is suppressed to the west and bring chances for rain to South Central TX. Looking beyond the long term period (famous last words of a meteorologist) long range model guidance is beginning to suggest a tropical wave amplifying as it moves out of the western Caribbean and into the southern Gulf of Mexico. It is far too early to know what will come of this disturbance. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 79 98 78 100 78 / 20 20 0 - 0 Austin Bergstrom Intl Airport 78 98 77 99 77 / 20 20 0 - 0 New Braunfels Muni Airport 77 98 76 99 76 / 20 20 - - 0 Burnet Muni Airport 76 96 75 98 75 / 20 20 - - 0 Del Rio Intl Airport 80 102 80 104 80 / 30 10 10 0 0 Georgetown Muni Airport 77 98 77 100 77 / 20 20 0 - 0 Hondo Muni Airport 77 101 76 102 76 / 30 20 - - 0 San Marcos Muni Airport 77 98 76 99 76 / 20 20 - - 0 La Grange - Fayette Regional 78 99 77 100 78 / 20 30 0 - 0 San Antonio Intl Airport 79 98 78 99 78 / 20 20 - - 0 Stinson Muni Airport 79 98 78 99 78 / 20 20 0 - 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Aviation...Huffman Short-Term/Long-Term...05
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1012 PM EDT Wed Aug 14 2019 .SYNOPSIS... Slightly drier air will filter into the forecast area to end the work week, limiting chances for afternoon and evening storms Thursday and Friday. Moisture will begin increasing again by the end of the weekend as a Bermuda high strengthens over the western Atlantic Ocean. A weak area of tropical low pressure and associated moisture may impact the Southeast early next week. && .NEAR TERM /THROUGH THURSDAY/... As of 1010 PM: Shower and thunderstorm activity has ended across the region and will send out an update shortly to reflect that. A few isolated showers are possible until around midnight along remnant outflow boundaries south of Charlotte. Latest RAP guidance shows moisture convergence associated with weak northerly upslope flow in the mountains and south of Charlotte. These areas along with the Lakelands of the Upstate have the highest odds of patchy fog and low clouds for tonight. Light northerly flow atop the region should limit dense fog formation outside of the most protected mountain valleys. Temperatures and dewpoints bottoming out in the upper 60s to near 70 will make for another muggy August night. The axis of the 500mb trough shifts slightly eastward for Thursday afternoon; drier air will filter in above the PBL as a high pressure center builds across the Mississippi Valley. With the pattern still not having changed much, some low PoPs continue to be warranted along and east of the Escarpment. Temps will trend down slightly compared to today. The availability of the drier air has two effects: it suggests greater potential for dewpoints to mix out and further reduce the impact of heat index, but also suggests any storms that do form will be more likely to generate a severe microburst--though the risk still looks isolated. The risk is not enough that SPC has noted us on the Day 2 outlook. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 210 pm Wednesday: Surface trough will remain across the forecast area through at least the first half of the short term, delineating unseasonably low theta-e/PWAT air (over much of our area) from a more tropical air mass (closer to the coast). As such, fairly robust boundary layer mixing will result in surface dewpoints falling off into ~the mid 60s across much of the area Friday afternoon, and all but perhaps the extreme southeast zones are expected to see little in the day of significant instability during that time. As such, pops for diurnal convection are unseasonably low, with 20% chances limited to the extreme southeast tier of the forecast area. By the end of the period, a strong Bermuda high is forecast to begin showing signs of retrogression toward the Southeast Coast, allowing for a moist southerly flow to become established across much of the region, allowing for some degree of moisture return. The most interesting aspect of the entire forecast revolves around the potential for tropical/subtropical low development, which most major model guidance depicts in some form or another, but with fairly wide disagreement regarding timing/location/intensity. While this would most likely impact our area (if it impacts our area at all) during the medium range, some guidance sources suggest moisture from this feature could impact the area as early as late in the short term. At the very least, increasing low level moisture/instability supports increasing pops to 20-30% across the forecast area for Saturday afternoon. Temps are forecast to be right around normal through the period. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 225 pm Wednesday: Eyes will be on the tropics (subtropics?) for the medium range, with the latest 12Z run of the ECMWF being of particular interest for our forecast area in bringing a tropical or perhaps hybrid area of low pressure straight through the heart of the western Carolinas Sunday through Sunday night. However, to say that confidence in any one deterministic model solution is low at this point would be quite the understatement. The latest GFS never really achieves notable surface development, while the Canadian GEM offers weak development that remains confined to the coast. Regardless, pops will be on the increase through the period, as southerly flow deepens west of rather strong Bermuda high. In terms of the forecast, this will be manifest as pops for diurnal convection creeping above climatology by Sunday afternoon, continuing through the end of the forecast period. Temps are generally forecast to remain near climo, although maxes could slide a little below normal in light of increasing cloud cover. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: Moderate confidence in 00Z TAFs. An isolated shower or thunderstorm can`t be completely ruled out at any TAF site through 04Z including KCLT, mainly forming around remnant outflow boundaries. Low clouds and patchy fog is likely for mountain valleys tonight including KAVL, although light northerly flow across the region should limit cigs/vsbys to IFR/LIFR or higher. There is a 10 percent chance of these conditions occurring at other locations including KCLT. Any low cigs/vsbys should rapidly improve around 12Z. Convection will be more isolated for Thursday with ridgetops, foothills and I-77 corridor including KCLT having about a 40 percent chance of shra or tsra sometime between 20Z and 00Z. Outlook: The passing frontal boundary will remain stalled SE of the area through Saturday, with lower end convective chances persisting. Convective activity will likely be on the increase late this weekend into early next week. Early fog/stratus will be possible each day across mountain valleys. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 100% High 89% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 90% Med 66% High 97% High 100% KHKY High 100% High 95% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JDL NEAR TERM...Munroe/Wimberley SHORT TERM...JDL LONG TERM...JDL AVIATION...Munroe
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
955 PM EDT Wed Aug 14 2019 .SYNOPSIS... A cold front will slowly approach the area through Thursday then dissipate over the region this weekend. High pressure offshore will dominate early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... As of 940 PM Wednesday...Showers and storms were most active over southern and western portions of the CWA this evening and continue at late evening over the Coastal Plains. Will leave high chance PoPs in over these areas for the next few hours as storms should gradually dissipate. HRRR and 3km NAM show redevelopment of convection close to the coast early in the morning and will continue to trend forecast in that direction with high chance PoPs. No changes needed to forecast temperatures as very warm and humid conditions persist with continued above climo lows well into the 70s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... As of 230 PM Wed...Area will remain in the moist warm sector with front to the west, as weak shortwave energy continues to move through the flow aloft. Expect isolated to scattered showers and storms early, becoming scattered to numerous in the afternoon and evening. Increased pops to likely for most of the area with good agreement between guidance (NSSL-WRF, HREF and HRRR). There is still a marginal severe threat, with damaging winds possible, but main threat still looks likely locally heavy rain with PWATS 2.25-2.5". Highs in the upper 80s to low 90s, with heat index values around 100 deg. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 230 AM Wed...A cold front will approach the area through late week leading to unsettled weather. The front will gradually dissipate over the region this weekend. Fri through Tue...Better moisture begins to shift to cst late in week into the weekend as the front sags into the area and gradually dissipates. Will keep chc pops for the cst with mainly slight chc inland thru Sunday. As offshore high pres becomes dominant early next week expect wdly sct activity. With hgts building a bit over the weekend into early next week and mdls now not showing much E to NE wind raised temps a bit with highs around 90 or low 90s inland with mid/upr 80s beaches most of the period. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Short Term /through Thursday/... As of 750 PM Wed...Largely VFR conditions this evening with the exception of sites impacted by decaying showers and occasional thunderstorms. Expect coverage to wane with loss of heating but in the near term occasional sub-VFR conditions are possible at all sites except PGV. Patchy fog and stratus are possible late tonight into Thursday morning although with expected lingering cloud cover confidence is lower than average. Some brief IFR is possible. VFR returns by mid-morning with scattered showers and thunderstorms expected again by the afternoon and evening with brief sub-VFR conditions possible. Long Term /Thursday night through Monday/... As of 230 AM Wed...Deeper moisture begins to shift mainly E of taf sites Fri into the weekend with less shra/tsra coverage and mainly VFR. As usual some patchy fog/st poss early morn espcly after most areas see decent rainfall. && .MARINE... Short Term /through Thursday/... As of 955 PM Wednesday...Minimal changes needed to marine forecast as SW winds continue at 10-20 knots with seas of 2-4 feet. The gradient relaxes a bit Thu with SW winds 10-15 kt. Seas of 2-4 ft will persist through Thursday, but may see some 5 ft on the outer central and southern waters. Long Term /Thursday night through Monday/... As of 230 AM Wed...The weakening front tries to push into the area Fri and Sat but looks like will dissipate with any post frontal winds very light with dir grad becoming S/SE again later Sat and SSW Sunday aob 15 kts. Seas mainly 2 to 4 ft thru pd. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...CTC SHORT TERM...CQD LONG TERM...RF AVIATION...RF/MS MARINE...RF/CTC/CQD
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1106 PM CDT Wed Aug 14 2019 .UPDATE...For 06Z Aviation discussion below && .SHORT TERM...(This evening through Thursday night) Issued at 245 PM CDT Wed Aug 14 2019 Short term concerns remain convective trends into Thursday afternoon/Thursday night. Some heavier cumulus across southern MN with little in the way of any radar returns associated. HRRR is gradually backing away at its isolated shower threat late this afternoon. Will leave the area dry overnight. Models indicate we will keep some form of mid cloud deck across the CWA during the night associated with the incoming weak short wave over southern Manitoba Canada at this time. This may this may limit overall extent of fog formation. Also, some drier air did work into the eastern CWA during the day and will likely limit overall fog threat as well. We did keep patchy wording for now. Deterministic models diverge some on timing of next short wave trough, with the ECMWF most consistent on moving it into eastern Dakotas later Thursday afternoon. Expect some sunshine will warm temepratures through the upper 70s most areas to the east by Thursday afternoon. We continued to ramp up PoPs to likely over west central by 00z Fri. Does look like forcing will be strong enough and instability great enough for at least a small threat of severe weather into the evening over western MN. 12z HREF drive some hail/wind potential into west central MN. Will bring likely PoP east into eastern MN as the upper trough moves through 06z-09z Fri. It appears overall instability wanes overnight. .LONG TERM...(Friday through Wednesday) Issued at 245 PM CDT Wed Aug 14 2019 With the long term period beginning on Friday morning, overnight precipitation should be exiting to our east. After that, we will have one main chance of potentially widespread precipitation on Saturday evening. The remainder of the period looks to be mostly dry, with a warming trend for the middle of next week. There are still timing differences with pushing the Thursday night/early Friday shortwave east of our area, so we still carry chance pops in eastern MN and western WI as that wave departs Friday. Meanwhile, a strong low pressure system advancing eastward across northern Saskatchewan and Manitoba will drag a trailing cool front across the Dakotas Saturday and into Minnesota most likely Saturday night. The strongest forcing will likely stay north of our area, closer to the upper jet, and a separate shortwave across Iowa will focus additional lift there. Still expect showers and thunderstorms to move through along the front, but with the strongest forcing to the north and south of us, it`s uncertain at this point as to how widespread precipitation will be locally. Mid level lapse rates are marginal and with MUCAPE under 1,000 J/kg, severe weather chances are quite low. Individual storms could produce temporary heavy rainfall, but overall the flooding threat is also low. High pressure will follow into early next week and push east of our area by Tuesday. This will lead to southerly flow developing and the western CONUS thermal ridge expanding eastward leading to warming conditions by Wednesday and Thursday. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1106 PM CDT Wed Aug 14 2019 Mid/high clouds will initially inhibit fog overnight, but models/satellite indicate some scattering from the west so still cannot rule out some patchy development. Expect an increase in mid-level clouds on Thursday, especially during the afternoon. Shower and thunderstorms look to spread eastward across the MN portion of the area between 23Z Thursday and 06Z Friday. Light and variable winds overnight become south-southwest on Thursday morning ahead of the trough. KMSP...There could be patchy fog around during the morning push, but expect visibility at the site to remain VFR. Otherwise, increasing low-end VFR clouds on Thursday afternoon with shra/ts chances returning around/after 03Z Friday. /OUTLOOK FOR KMSP/ Fri...VFR with MVFR/TSRA possible early. Wind S 5-10 kts. Sat...VFR with MVFR/TSRA possible. Wind SW 10 kts. Sun...VFR. Wind SW 10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...DWE LONG TERM...SPD AVIATION...LS
Area Forecast Discussion
National Weather Service Marquette MI
731 PM EDT Wed Aug 14 2019 .SHORT TERM...(This evening through Thursday) Issued at 411 PM EDT WED AUG 14 2019 WV imagery and RAP analysis indicated a low amplitude pattern with a mid/uper level ridge over the southwest CONUS and a broad trough from northeast Canada through the Great Lakes resulting in wnw flow toward Upper Michigan. An upstream shortwave trough located over southern Manitoba with limited moisture available supported mainly an increase in mid/high clouds. Otherwise, with surface high sprssure building across the northern Great Lakes, Vis loop showed clear to partly cloud conditions with fair weather cu over inland locations. Tonight, favorable radiational cooling conditions during the early overnight period should allow temps to again drop into the low to mid 40s before mid clouds move in late and thicken ahead of the shrtwv, especially over the west half. The clouds should also limit potential for fog development. Thursday, the shrtwv could bring some light showers or sprinkles into the west early. However, expect a better chance for isold/sct shra/tsra in the afternoon inland west, especially along lake breeze boundaries, as daytime heating pushes MLCAPE values to near 500 J/Kg. With only marginal instability and 0-6km shear to around 25 knots, no strong/svr storms are expected. .LONG TERM...(Thursday night through Wednesday) Issued at 307 PM EDT WED AUG 14 2019 The large-scale CONUS pattern continues to be one of southern U.S. ridging and an active subtropical jet with multiple short waves on its northern periphery keeping our weather locally unsettled at least through the weekend. The first chance of showers will be late tomorrow night over the far west as a mid-level short wave approaches from the southwest. Forcing with this wave will spread across the rest of Upper Michigan during the day Friday, though ascent is not particularly strong. The models struggle to destabilize beyond perhaps 1000 J/kg MLCAPE in just a few pockets, again mainly west, so not too enthused about thunderstorm chances on Friday, though there could be at least a few rumbles. As the wave lifts off to the northeast Friday night, heights rise briefly, though another subtle short wave quickly approaches. Models shear it out enough that we don`t get any showers from it, but it probably will be enough to keep clouds around early Saturday. The next big weather-maker will be a cold front approaching from the northwest on Saturday. Still some timing uncertainty with the EC slower than the American guidance. Right now, the timing isn`t favorable for widespread thunderstorms with the front moving through late Saturday night or early Sunday morning, though if the slower EC verified there could be a window for storms on Sunday. Unfortunately because of this timing uncertainty, had to carry shower and storm chances for nearly all of Saturday and Sunday in this package. But in reality there will likely be a decent dry period one of the two days; stay tuned as we narrow that window down. High pressure builds in behind the front and it looks like we`re dry Monday through at least the middle of next week, except for maybe a pesky shower or two over the west Tuesday night. Some of the models try to reintroduce more summerlike temps by the end of the week, but still plenty of time to watch that. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 730 PM EDT WED AUG 14 2019 VFR conditions continue through the forecast period, along with winds less than 10 knots. Still some potential for ground fog in the KIWD area later tonight but with mid clouds moving into that area later this evening expect fog threat to be very limited and have left out of the forecast at this time. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 411 PM EDT WED AUG 14 2019 Winds over the lake are expected to stay at or below 20 knots through Saturday. Models are indicating the chance for an active period of weather this upcoming weekend. Expect chances of showers and thunderstorms through the weekend as well as the chance at gusty conditions, up to 25 knots, Sunday morning through Sunday evening. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...RJC AVIATION...RJT MARINE...JLB
Area Forecast Discussion
National Weather Service Pueblo CO
259 PM MDT Wed Aug 14 2019 .SHORT TERM...(This evening through Thursday) Issued at 238 PM MDT Wed Aug 14 2019 Some isolated showers/tstms will be possible into the early evening over the mtns and high valleys, but the I-25 corridor and eastern plains will be the main focus area for storms this evening as a weak weather disturbance moves across the area. Isolated to scattered storms are expected across portions of the I-25 corridor and plains, with the are east plains likely see the best chances. The HRRR shows only some isolated storms, The NAM Nest has a little more coverage over the plains, with the potential for some strong storms early in the evening over Otero and Bent Counties, and then after about 7 pm, some strong storms moving into Kiowa and eastern Prowers Counties. The earlier run of the NAM has showers/tstms continuing over the far southeast plains into the late night hours, but the 18Z run, as well as the lastest HRRR, shows activity ending by about midnight or 1 AM. SPC still has the southeast plains outlooked for the possibility of severe storms, with the main threats being large hail and damaging wind gusts, but with shear values of 40+ kts cannot rule out an isolated tornado. On Thu a northerly surge moves through eastern CO by around midday, and conditions look drier. Dew points this afternoon over the southeast plains are in the 50s, but Thu afternoon they are expected to drop into the 30s along the I-25 corridor, with some lingering lower 50s over the eastern border area, while over the high country dew points should be mostly in the 20s to lower 30s. There will likely still be a be enough moisture and instability for a just a few showers and tstms. Temps on Thu will be warmer across the plains, with 90s for highs, with some locations along the Arkansas River Valley see highs nearing 100. The San Luis Valley and the Upper Arkansas River Valleys should see highs in the lower to mid 80s. .LONG TERM...(Thursday night through Wednesday) Issued at 238 PM MDT Wed Aug 14 2019 Flat westerly flow across the area will keep best mid level moisture shunted fairly south of the region into the weekend, before upper ridge amplifies over the Rockies early next week, leading to a brief influx of deeper moisture Tue/Wed. Beginning with Friday, low level moisture in place across the plains early mixes eastward by late day, though perhaps just enough instability/moisture linger for isolated afternoon/evening convection along and east of the mountains. Best chance for a stronger storm would be over the far east and up into nern CO, where greater instability will reside. Sat will features a low risk of some high based storms over the mountains and Palmer Divide Sat as upper wave slides by to our north, while max temps begin to creep back upward a few degf at many locations. Sun/Mon look dry and hot, with only some very isolated weak convection possible over the mountains Mon afternoon. Moisture returns Tue/Wed under building high pressure aloft, with thunderstorm chances increasing both days, especially across the mountains. Max temps will remain warm, with lower Ark Valley again near 100f both days. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 238 PM MDT Wed Aug 14 2019 Showers and thunderstorms will be possible thru early this evening at KALS, KCOS and KPUB. If storms do move into the vicinity of a terminal forecast site, the main threats will be gusty outflow winds and lightning. Otherwise, VFR conditions are expected. Otherwise VFR conditions are expected tonight and Thu. Chances for showers and thunderstorms look lower on Thu. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...PETERSEN AVIATION...28
National Weather Service Raleigh NC
932 PM EDT Wed Aug 14 2019 .SYNOPSIS... A series of surface boundaries will likely stall and slowly dissipate across central NC through late week. This will keep unsettled and very humid conditions in place. && .NEAR TERM /TONIGHT/... As of 932 PM Wednesday... The main cold front continued to weaken and remain well NW of our region this evening. Therefore, much of NC continued in the very humid air mass with surface dew points ranging in the lower 70s NW into the upper 70s in the Coastal Plain. The depth of the moisture was larger in the SE, where the 00Z/15 observed data indicated Perceptible Water (PW) values near 2.25 inches across SE NC. These readings tail off a bit to the NW, where readings were still 1.75 inches in the Triad region. Showers and thunderstorms have been more isolated in the NW where the moisture depth is lower and convergence has been lacking. In the east, showers and thunderstorms have been generally scattered and associated with a weak trough over the Piedmont, and along outflow/sea breeze boundaries that raced NW into the Coastal Plain and southern part of NC. Several thunderstorms have clustered in the vicinity of Johnston/northern Sampson/NW Wayne and Wilson Counties where these boundaries were merging. It appears that the showers and thunderstorms will be focused along the merging boundaries over the eastern Sandhills, far SE Piedmont, and Central Coastal Plain through around midnight. This is the region where observational data including surface moisture convergence, instability, and lift support the radar trends and CAM forecasts support continued development until the instability is worked over. Smithfield, Wilson, and areas NW of Goldsboro appear likely to get locally heavy rain of 2+ inches. Additional widely scattered showers/storms may develop near the boundaries in the next few hours, mainly extending from near Southern Pines to Raleigh and Rocky Mount. Otherwise, little if any additional showers are expected. Some stratus/fog appears likely late tonight given the nearly saturated air mass. Lows hold above 70 to the mid 70s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... As of 440 PM Wednesday... A complex forecast continues in the short term as a low amplitude trough axis remains centered over the Ohio Valley. This morning at 500 mb a potent shortwave was analyzed back in Oklahoma. This wave is forecast to continue to push southeast and round the base of the trough. The wave will then push over North Carolina Thursday afternoon. A significant amount of model discrepancy exists here as the RAP holds the wave somewhat together while the GFS shears it apart. One thing that is rather consistent though is an upper level jet will strengthen across the North Carolina Mountains. As this occurs central North Carolina will be placed in a RRQ with upper level divergence increasing. This working in tandem with the approaching shortwave will provide more than sufficient lift. ML CAPE values are again being advertised around 2000 J/kg with SFC to 6 km shear forecast around 30 kts. PWATs are forecast to be around 1.75". Given the more than sufficient PWATs, instability, and lift showers and thunderstorms appear likely. Shear values which are around 30 kts would support some multi- cell clustering. SPC has central/eastern North Carolina in a marginal risk to account for this. Damaging wind gusts will be the primary threat. High temperatures Thursday will be near normal, or around 90 degrees. Thursday night a cold front will approach from the west with the upper level jet located over central North Carolina. Lower PWAT air will slowly filter into the northwest Piedmont before the front stalls across central North Carolina. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... As of 240 PM Wednesday... Fri/Fri night: The surface boundary extending through the E Piedmont early Fri is expected to drift back NW into the Foothills, propelled in part by the westward-expanding Atlantic ridge. A very subtle shear axis will hold over the coastal Carolinas, and forecast soundings depict a fairly dry column west of this feature, including western and much of central NC, with PW under 1.5" NW of the Triangle. Will maintain the general flavor of the current forecast with chance pops SE of Highway 1 and low to no pops to the west, peaking in the afternoon followed by diminishing pops after nightfall. High PW down east and meandering cell movement within weak steering flow may result in pockets of high rainfall totals there. Highs around 90 to the lower 90s, followed by lows of 69-76 with areas of fog/stratus likely to develop, mainly E, overnight. Sat through Wed: A humid pattern with above-climo pops is expected this weekend into early next week, as the main band of westerlies holds well to our N. A weak mid level trough axis will hold to our W, as Atlantic ridging attempts to build westward over the Southeast coast through the period. A stream of high PW (over 2") sets up through central NC, propelled inland from the coast over the weekend with the building offshore ridge. Will carry good shower/storm chances, focused during (but not limited to) the afternoon and evening/early overnight hours. The greatest chance may occur this weekend, as an 850 mb low located over E GA Sat afternoon tracks NE through the Carolinas, bringing the potential for a shot of enhanced low level moisture flux Sat night through Sun, and will show an uptick in pops, mainly E, during this time. There is a band of comparatively drier air, now noted on the west side of the Atlantic ridge on GOES channel 9 WV imagery, that the models show swinging W then NW, perhaps brushing through Eastern NC late Mon night through Tue, which may lead to a relative lull in pops during this time frame, providing a glimmer of dry hope within what should otherwise be a muggy pattern with at least some pop every day, along with a nearly daily risk of early-morning stratus/fog. Low level thicknesses trend from slightly above normal over the weekend into Mon to near normal Tue. Expect both highs and lows to edge a bit warmer than usual. -GIH && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 805 PM Wednesday... Scattered showers and storms will dissipate in roughly the region bounded by RDU, FAY, and RWI during the next few hours, where outflow boundaries are about to merge there. Otherwise, areas of low stratus and fog (IFR-MVFR) are expected to develop late tonight- early Thu, with the associated moist layer expected to yield occasional MVFR ceilings as it is heated and lifted into VFR range by early Thu afternoon. Scattered convection will develop/occur within a convergence zone provided by an Appalachian lee trough/old front over cntl NC Thu aft-eve, but with a pulse-type/random nature that yields low predictability of precise timing and location until just a few hours prior to occurrence. Outlook: Areas of stratus and fog are likely to develop again Thu night, followed by patchier coverage each morning through the weekend. A climatological chance of diurnal, pulse-type storms will also exist through the weekend. && .EQUIPMENT... Twice daily upper air flights from GSO are scheduled through 12Z Fri/16th. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett/Haines NEAR TERM...Badgett/Haines SHORT TERM...Haines LONG TERM...Hartfield AVIATION...Haines EQUIPMENT...RAH
Area Forecast Discussion
National Weather Service Tucson AZ
803 PM MST Wed Aug 14 2019 .SYNOPSIS...Excessive heat will remain as the primary concern for Thursday and Friday. A small increase of moisture will promote additional thunderstorm activity for the next few days but will remain relatively subdued due to a poor monsoon pattern. && .DISCUSSION...It was a quiet afternoon today with the high pressure overhead inhibiting convective development. There was a small moisture intrusion from the southeast that allowed for isolated thunderstorms to develop, mainly over mountains south and east of Tucson. The dewpoint struggled to reach 40 for Tucson midday and 00Z sounding only had a PW value of 0.79. The main story was the max temperature of 107 which tied the record set for this day. Its unusual to have these high temperatures in August and tomorrow will be even hotter for a forecast of 109 which will be just under the record of 110. As such, an excessive heat warning is in effect for Tucson until Thursday evening and for other lower desert areas until Friday. GFS and ECMWF show a splitting high overhead which is depressing convective activity. A weak southeasterly flow in the mid levels allow for some moisture transport from Sonora to support convection Thursday afternoon. Storm development will likely remain mountain bound to the south and east of Tucson and over the White Mountains. UA WRFNAM is probably the most excited for convection, but other HiRes models concur with the lack of activity. As the highs split, the mean flow becomes more westerly on Friday preventing moisture from aiding convection for the rest of the weekend. The mean flow will slowly starting shifting southeasterly and then easterly early next week as the high slowly migrates back to the four corners area. This should allow for a small uptick in thunderstorm activity compared to the weekend. However, it will remain relatively weak for this time of year. Higher temperatures will return as the high rebuilds over AZ. && .AVIATION...Valid through 16/06Z SKC-FEW to the west and north of KTUS. SCT-BKN at 25k ft MSL mainly to the east which inlcude KOLS/KDUG. Winds generally remain under 10 kts. Isolated TSRA/SHRA expected Thursday afternoon and evening, mainly near mountains, but within vicinity of KOLS/KDUG. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Dry and hot conditions are expected across most of southeast Arizona through Friday with only slightly cooler conditions into the weekend. Moisture will then begin to increase across eastern areas later Thursday, with isolated to perhaps scattered showers and thunderstorms primarily from Tucson east and south Thursday through the upcoming weekend. Aside from gusty thunderstorm outflow winds, wind speeds remain light and terrain driven through the weekend. Minimum Relative Humidity values will be in the 10-20 percent range in the valley locations through Friday, with only a modest increase in values over the weekend, before likely dipping back into the teens by next week. && .PREV DISCUSSION... /issued 259 PM MST Wed Aug 14 2019/ Heat with a low-grade monsoon pattern into next week. Strong high pressure overhead today and tomorrow for near record heat across Southeast Arizona; especially from Tucson into the lower deserts. We`re still pretty dry today with surface dew points in the upper 30s to lower 40s across the area and precipitable water values around 60 percent of normal at about 1 inch (plus or minus a tenth). As you might expect, much deeper moisture in central Sonora southward along the Sierra Madres and west coast of Mexico. A weak and shallow surge is working up the Gulf of California, and the HRRR continues to advertise a strong outflow pushing into our area from northern Sonora convection this evening. That should give us enough moisture for a few more storms Thursday and Friday afternoons. As high pressure continues to spread westward and buckle a bit, our flow will weaken and then gain a westerly component at most levels by late Friday. This will tend to limit additional significant moisture gains and keep our thunderstorm coverage rather pedestrian with below average activity for mid August. Ensembles and ensemble means continue to show good support for strong high pressure rebuilding over Arizona and New Mexico the first half of next week. We will probably end up with another bout of excessive heat by next Tuesday and Wednesday. We may have enough moisture around to help moderate that a couple of degrees, and if the high center reconsolidates in a more favorable position to bring back southerly and/or easterly flow we should manage a few more storms (hopefully around next Wednesday or so). && .CLIMATE...Near to record highs today and Thursday and possibly on Friday. Below are forecast high temperatures and the record high for today August 14th and tomorrow August 15th for select locations across southeast Arizona. DATE Aug 14 Aug 15 Fcst Rcd/Year Fcst Rcd/Year Tucson Intl Airport 107 107/2015 109 110/2015 Bisbee-Douglas Airport 100 100/2010 97 101/2015 Ajo 111 113/2012 113 113/2015 Kitt Peak 89 88/1962 90 87/1962 Organ Pipe Cactus 111 112/2015 112 112/2015 Picacho Peak 111 110/2015 111 111/2015 Safford Ag Station 105 105/2015 105 106/2015 && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST Thursday for AZZ504-506- 509. Excessive Heat Warning until 7 PM MST Friday for AZZ501-502-505. && $$ Pawlak Visit us on Facebook...Twitter...YouTube...and at