Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/24/19

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
931 PM MDT Tue Apr 23 2019 .UPDATE... Accumulating snowfall has ended over the higher terrain of northern NM therefore the Winter Storm Warning has been cancelled. The next weather element to examine will be fog and low cloud development overnight across parts of eastern NM, particularly the Caprock area of Roosevelt and Curry counties. The latest HRRR and RAP guidance shows low vis developing after midnight but MOS guidance indicates only low cigs. Will take another look prior to an 11 pm update to see if expansion of the Dense Fog Advisory is warranted. Guyer && .PREV DISCUSSION...521 PM MDT Tue Apr 23 2019... .AVIATION... 00Z TAF CYCLE Another round of rain showers, a few thunderstorms and northern mountain snow showers with widespread mountain obscurations will continue into tonight. Some clearing will begin overnight which may lead to IFR ceilings and fog forming. This is most likely at KLVS, but could also occur and KSAF, KTCC and KROW. Some residual showers and mountain snow showers will be possible tomorrow over the northern portion of the state, otherwise dry and warmer Wednesday with VFR conditions expected. && .PREV DISCUSSION...322 PM MDT Tue Apr 23 2019... .SYNOPSIS... Showers and thunderstorms will continue through evening. Some storms near and south of I-40 will contain heavy rain, small hail and gusty winds, while the high terrain of the northern mountains may see light snow. Fog has also developed around Clines Corners and this fog may expand overnight across the east central plains. Visibility near one quarter mile is possible. On Wednesday through Friday, a few storms are still possible across the high terrain during the afternoons and evening, but coverage will be less than today. Temperatures will warm to back above normal. However, another storm system is on tap early next week. && .DISCUSSION... A slow moving upper level low pressure system will continue to track eastward across Mexico tonight. Diurnally driven convection has developed this afternoon, aided by lift from both the upper low and low level moist upslope. 90th percentile PWATS combined with modest instability across southern NM thanks to breaks in the clouds, have allowed for both small hail and heavy rainfall in the stronger storms. Once the sun sets, and the trough axis shifts over eastern NM after midnight, storm coverage will decrease significantly. A slight chance for persistent storms will remain possible across the far southeast portion of the CWA north of the stalled frontal boundary. However, it is believed that most of the precip will remain south of Chaves County. Meanwhile, fog has developed near Clines Corners and this will likely continue, if not expand overnight across much of the east central plains. Have issued a Dense fog advisory for Clines Corners, which again, may be expanded later tonight. Recycled moisture and daytime heating will allow for enough instability for a few storms to develop across the higher terrain on Wednesday. Coverage will decrease significantly from today, and storm motions will be toward the south. An upper level ridge will move over the Desert Southwest on Thursday while a weak back door front nudges into northeast NM. Still, the moisture will not be entirely scoured out, thus, a few more storms will be possible across the high terrain. The Sangre de Cristo Mountains will be favored as the low level upslope flow behind the front will help focus storm development. On Friday, the ridge will flatten some, and allow westerly winds to increase. The NAM is suggesting that a little convection may develop over the high terrain and shift eastward. Since it will be somewhat drier, should storms develop, some dry lightning would be possible. Another front will nudge into northeast NM on Saturday, and the GFS is bullish with regards to QPF across NE NM behind the front. That said, the GFS also shows the front continuing south and westward into Sunday, while the ECMWF largely has the front washing out. This front is the beginning of some large discrepancies in the extended. As the surface winds veer around to the south, the GFS brings up Gulf moisture into the eastern plains on Sunday, but the ECMWF is drier with westerly winds until it has a front of it`s own early Monday. Both models show the next storm system moving toward the Four Corners Monday night and crossing Tuesday, though the ECMWF is slightly slower. The slower ECMWF draws up much more Gulf moisture, adding to the potential for more wetting rains across eastern NM, while the GFS is faster and brings more wind to the state. 34 && .FIRE WEATHER... A wetting event continues as the Pacific low turns east across northern Mexico, although wetting precipitation is becoming more isolated as the the atmosphere becomes increasingly convective this afternoon. Solid wetting precipitation noted from the overnight and early morning hours across much of central and eastern New Mexico. Precipitation will diminish after midnight as the upper low pulls further southeast toward far west Texas. A warming/drying trend will begin Wednesday and continue into the weekend as a broad upper level ridge gradually shifts east over the region. However, sufficient moisture will remain for limited rounds of showers and storms each afternoon/evening over the higher terrain. The westerlies will begin to trend up Friday afternoon as the ridge flattens, along with Haines indices and the potential for dry lightning given limited remaining moisture and a drier lower boundary layer. The potential for critical fire weather conditions will trend up over the weekend and into Monday in advance of another Pacific low approaching from over southern California. However, fire growth potential may be significantly limited by recent wetting precipitation and green-up. 11 && .ABQ WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 9 AM MDT Wednesday for the following zones... NMZ523. && $$ 42
National Weather Service Burlington VT
730 PM EDT Tue Apr 23 2019 .SYNOPSIS... After another sunny day across the North Country, cloud cover will build back into the region this evening. A cold front will sweep through the region during the overnight hours with widespread rainfall amounts ranging from a quarter to a third of an inch. Rain showers will continue behind the front on Wednesday but will likely be confined to the higher terrain. Showers will then taper off Wednesday evening with drier conditions expected to continue through Friday morning before another cold front approaches the region from the west. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... As of 730 PM EDT Tuesday...Going forecast is in great shape with only a slight tweak needed to precip onset and end timing. Showers are moving into western portions of the CWA currently and latest trends show the bulk should clear northern New York during the 03-05Z hours and eastward across Vermont from 06-09Z. Some question with the latest 18Z guidance as to how much upslope precipitation develops after 09Z, but have left the forecast intact for now and will assess the upcoming 00Z guidance for any potential changes. Other change was to remove mention of any thunder as this afternoons activity has all but gone away with no convection noted in the upstream obs/radar. Previous Discussion...Skies cleared nicely throughout the day with the axis of mid-level ridging moving across the North Country. The subsidence can be seen nicely on satellite imagery and even continues to suppress any cumulus from forming given temperatures once again in the mid 60s to near 80 degrees. RAP soundings suggest 100 to 400 J/kg of CAPE yet CIN of -50 to -70 J/kg hints at why diurnal cumulus has been hard to come by. That all will change tonight as rather dynamic shortwave interacts with a developing upper level low tracking across the international border. Convection with this system can already be seen across western New York and western Pennsylvania and all CAMs show the system entering a more "energetic" air mass that hasn`t been capped by cloud cover. As this happens, the frontal boundary associated with the upper level trough will begin to pick up some speed and develop additional convection as it crosses New York. While there is some CIN in place, it looks like the front will be able to lift surface parcels above the subsidence inversion and allow for some convective showers and maybe even a thunderstorm or two to track into northern New York after sunset. The loss of diurnal heating will limit convection heading into the overnight period across Vermont but enough mid- level forcing should still allow for convective showers to continue, albeit a near nil chance for thunderstorms. Overall rainfall amounts through tonight will be widespread quarter to a third of an inch of rainfall. As the upper level low tracks eastward toward Newfoundland, recycled Atlantic moisture will wrap around the low and move back into the North Country. In addition, with cold air advection behind the low, we will see in increase in mid-level lapse rates which will help produce additional showers on Wednesday; especially during the morning and afternoon hours. The majority of these showers will fall on the western slopes of the Adirondack and Green Mountains with Froude numbers near 1. Some showers could back build throughout the day into the Champlain Valley but most rainfall accumulations will be restricted to the western slopes where an additional tenth to quarter of an inch of rainfall will be possible. This rain won`t be enough to cause any significant impacts on area rivers as levels have dropped nicely after the two precious heavy rain events. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 318 PM EDT Tuesday...Weak default ridging then builds briefly across the area during Thursday with partly sunny skies, light winds and seasonal temperatures from the upper 50s to mid 60s. Should be a really nice day for outdoor activities. By Thursday night our next system in the pipeline approaches with moisture streaming northeastward ahead of a sharply digging upper trough across the Great Lakes. The idea of thickening clouds later at night with increasing chances for showers across the southwestern half of the forecast area toward morning looks reasonable for now. This morning`s QPF/mass fields from the GFS seem overdone at this point and as such have largely ignored its output. Low temperatures to range from the upper 30s to mid 40s, slightly cooler far northeast where partial clearing will persist most of the night. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 318 PM EDT Tuesday...Much uncertainty exists in the extended portions of the forecast in regard to chances of rainfall. Complicating matters will be persistent and fast semi- zonal flow north of 40N at and above 500 mb which typically leads to large model spread in timing/strength of systems. Today is no exception with the GFS and Euro at odds with one another during much of the period and at times 180 degrees out of phase. For the sake of simplicity have downplayed pops into the lower probability ranges, especially from Sunday onward until more consistency is realized. The most confidence thus lies during the front end of this period (Friday/Friday night) when the aforementioned shortwave swings through the region with scattered/numerous showers. Otherwise the main theme for now with be variable clouds with on and off periods of partial clearing with temperatures averaging near or slightly below normal (mainly 50s and 30s). && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... Through 00Z Thursday...Conditions will be deteriorating overnight from VFR currently to MVFR this evening and through the much of TAF period with isolated IFR possible at KSLK and KMSS. Showers will shift across the area from 00-09Z with additional upslope showers possible at KSLK after 12Z. Restrictions in flight category will primarily be due to ceilings, but in some heavier showers brief MVFR visibilities are possible. Variable winds will shift to the south/southwest this evening and eventually west/southwest overnight with gusty winds to 25 knots possible Wednesday morning and afternoon. Outlook... Wednesday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Slight chance SHRA. Friday: Mainly VFR, with areas MVFR possible. Definite SHRA. Friday Night: Mainly VFR, with areas MVFR possible. Likely SHRA. Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA. Saturday Night: VFR. Slight chance SHRA. Sunday: Mainly VFR, with local MVFR possible. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Clay NEAR TERM...Clay/Lahiff SHORT TERM...JMG LONG TERM...JMG AVIATION...Lahiff
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1057 PM CDT Tue Apr 23 2019 .UPDATE.../SVR WATCH VAL VERDE COUNTY EXPIRES AT 11/ Predictably, the late afternoon runs of the HRRR were too aggressive with the Burro Mountain convective complex, and the mid evening runs displayed a more isolated picture for convection to roll off the higher terrain into the southern Edwards Plateau and western Hill Country in the early morning hours. Severe threat remains the same, only the likelihood of deep convection is lower due to current capping. This should weaken closer to daybreak, so will maintain the status quo on the 1 am - 7 am PoP grids, knowing the areas SE of the escarpment should see a lower coverage a deeper convection. A view of the mesoscale models versus the synoptic models offer two scenarios for heavy rain areas, and we are gaining confidence for a secondary precipitation maxima located over the eastern Hill Country for late Wednesday afternoon/Wednesday evening. This would assume the frontal/outflow boundaries from the overnight convection hangs up north of the CWA through daybreak. The pattern continues to suggest pockets of 4-6 inches is possible. && .PREV DISCUSSION... /ISSUED 746 PM CDT Tue Apr 23 2019/ UPDATE... Afternoon heating generated some scattered showers with tops to around 15 kft but showed no signs of breaking the cap. DRT 00z soundings arrived with a formidable cap at 8-10 kft, so expect no threat of evening storms forming in the eastern Hill Country and I-35 corridor counties. Updated to remove thunder for the evening for those areas. An approaching jet streak exit region late tonight could signal deeper convection chances ramping up after midnight west of DRT. While there does seem to be a slight radar increase trend to the distant SW, do not expect the past couple runs of the HRRR to verify with their depiction of a small complex moving as far east at Hwy 83. More isolated activity firing off the higher terrain and crossing the Rio Grande is what the consensus of models and even earlier HRRR runs have been saying. Watch to remain in effect for DRT, but likely any storms that impact Val Verde will be after the watch expires at 11 pm. Will plan to keep the watch running in case a time extension is needed. PREV DISCUSSION... /ISSUED 647 PM CDT Tue Apr 23 2019/ AVIATION... Most of the region has VFR ceilings as this new TAF period begins. The exception is SAT where it is MVFR. There are isolated showers across the area and some showers may move across any of the airports this evening. This will not reduce the flying category. Ceilings will lower later tonight eventually reaching IFR overnight. Chance for showers and thunderstorms will continue overnight. At DRT the best chance for thunderstorms will be late overnight. Thunderstorms will reduce visibility and bring strong wind gusts. Hail is also possible in storms. The best chance for thunderstorms in Austin and San Antonio will be late afternoon Wednesday. There is a slight chance that thunderstorms will bring severe hail (>1") or wind gusts (>50kts). The probability that any severe thunderstorm hits any airport is very low and we have not included this in the TAFs. Weather should improve after a cold front moves through the area Wednesday afternoon or early evening. Winds will shift to the north and ceilings will lift to VFR. PREV DISCUSSION... /ISSUED 354 PM CDT Tue Apr 23 2019/ SHORT TERM (Tonight through Wednesday Night)... An active short term forecast is expected for South Central Texas. For tonight, Severe Thunderstorm Watch 95 is in effect for Val Verde County through 11 PM CDT. Visible satellite imagery has shown nearly persistent cloud cover across Val Verde County through the day, which has helped limit overall destabilization, but nearly full insolation along the Serranias del Burro have resulted in an agitated cumulus field with the DRT radar showing developing showers. SPC Mesoanalysis shows over 50 knots of southwesterly effective bulk shear, encouraging additional thunderstorm organization. As these thunderstorms become more organized, convection allowing models indicate that these storms will make a run for the Rio Grande later this evening. Despite the cloud cover, dew points in the upper 60s are contributing to SBCAPEs in excess of 2500 J/kg which will help storms maintain themselves as they approach the Rio Grande. This will also allow them to advantage of steeper mid-level lapse rates of 7 C/km and encourage a large hail threat for parts of Val Verde. Farther north, convection continues to fire along a frontal boundary draped roughly along Interstate 20. Higher resolution guidance has been fairly consistent in advertising strong enough cold pool development with these thunderstorms that the cold front may actually be driven farther south than global guidance indicates by sunrise (into Central Texas/the Hill Country). Should this happen, this will set up the potential for training showers and thunderstorms as increasing forcing from an upper low diving across Chihuahua tonight into the Big Bend arrives. For the remainder of tonight, expect most of the shower and thunderstorm activity to remain relegated to the northern tier of counties with rainfall amounts up to one inch possible. During the day Wednesday, the location of the aforementioned frontal boundary will have huge implications for which areas see the heaviest rainfall but expect the frontal boundary to be near the northern border of the forecast area. The approach of the upper low will allow for the left front quadrant of an upper level jet to nose into Central Texas. While the initial approach of this upper level jet is expected to be during the morning hours (usually the most stable time of the day), increasing divergence aloft will help to accelerate rain rates across portions of Central Texas and the Hill Country. With forecast precipitable water values rising to near 1.5 inches, enhanced lift, and a slow-moving frontal boundary, have concerns that a localized flash flood threat may materialize for parts of the eastern Hill Country into Central Texas and have issued a Flash Flood Watch through the day Wednesday as a result. Current expectations for rainfall amounts in the watch area are in the 2 to 4 inch range, but isolated higher amounts in the 4 to 6 inch range appear possible based on ensemble plumes and high resolution QPF output. Based on these forecast amounts, rises to at least action stage on rivers and creeks are also possible during the day Wednesday. Despite persistent cloud cover during the day, at least some destabilization during the peak of the diurnal cycle and strong forcing for ascent will allow for some thunderstorm intensification during the afternoon hours. Cannot rule out some large hail, but expect gusty winds to be the main concern with freezing levels above 12,000 feet AGL and updrafts becoming water loaded as the thunderstorms translate east. Backed surface flow in the vicinity of the cold front may also create for an isolated tornado threat. Analysis of dProg/dt trends during the evening hours show the upper low beginning to accelerate away from the region and expect the flash flood and severe threat to taper off during the evening as the main system translates away from the region. A few showers and thunderstorms may linger Wednesday night as the system moves farther east. LONG TERM (Thursday through Tuesday)... The front and associated rain push out of the area by early Thursday morning, leaving the region in a NW flow. A gradual dry and warming period takes hold. As the subsequent surface high tails the front, winds will veer to a SE flow early Saturday. Broad ridging over the central CONUS will struggle to build over the weekend due to an embedded stream feature resulting in zonal flow aloft. The GFS is an outlier with handling this feature by deepening it as it moves over the Northern Plains and Midwest, then tries to bring a backdoor front into the region on Sunday. If this scenario proves true, limited moisture return to over the area would only result in a minimal amount of rain even if the forcing makes it to southcentral Texas. The warmest day of the forecast look to be either Sunday or Monday with highs for I-35 sites reaching the mid to upper 80`s and mid 90`s out west. With persistent SE flow for most of the long term period, clouds return over the area by Monday with the possibility of streamer showers developing on Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 74 59 78 60 / 50 100 90 20 10 Austin Bergstrom Intl Airport 65 74 59 78 60 / 50 100 90 20 10 New Braunfels Muni Airport 65 75 58 79 59 / 50 90 90 10 0 Burnet Muni Airport 64 70 57 75 58 / 50 100 70 20 10 Del Rio Intl Airport 66 80 58 86 60 / 60 80 20 0 0 Georgetown Muni Airport 64 72 58 76 59 / 40 100 90 20 10 Hondo Muni Airport 66 77 56 82 59 / 50 100 40 0 0 San Marcos Muni Airport 65 75 58 78 59 / 50 90 90 10 0 La Grange - Fayette Regional 67 78 61 78 60 / 30 60 90 20 10 San Antonio Intl Airport 67 75 59 80 60 / 60 100 90 10 0 Stinson Muni Airport 67 77 59 81 60 / 50 90 90 - 0 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from 7 AM CDT Wednesday through Wednesday evening for Blanco-Burnet-Gillespie-Hays-Llano-Travis-Williamson. && $$ Aviation...05 Short-Term/Long-Term...Oaks
Area Forecast Discussion
National Weather Service Houston/Galveston TX
940 PM CDT Tue Apr 23 2019 .NEAR TERM [Through Tonight]... Surface analysis this evening has surface front from west central Texas NE towards the Ozarks across Oklahoma. A few severe storms were located along the boundary moving out of the Big Country headed towards the DFW Metroplex. Outflow should re-enforce the front and allow it to push farther south tonight into Wednesday AM. Upper level trough over northern Mexico should push east tomorrow across Texas. This should support a couple different rounds of storms with heavy rainfall possible over the Brazos Valley during the late afternoon/evening and then down along the coast overnight. Squall line should move across the area overnight but capping may limit the overall severe threat. SPC has a slight risk over much of the area. Suspect the first round of storms towards the Brazos Valley will have the higher severe potential given weaker capping. Models hinting at a second increase in intensity of storms overnight as the squall line pushes east of Houston after midnight. There are still some timing differences in the WRF runs as well as HRRR runs. The real question mark will be how much the cap holds over SE Texas and if discrete cells can form which will become severe. Otherwise there could be a mix of convective modes and transition into more of heavy rainfall threat. Really the mesoscale yet again will be giving us fits on how the severe weather threat evolves tomorrow. Just now a really early look at the 00Z WRF-ARW and the 00Z HRR extended range - both models hit areas from near Brenham to Caldwell east to Huntsville/Crockett with high QPF. This swath is quite a bit farther south and east from where all the synoptic models place higher amounts of QPF. We will have to watch to see if any of the other models from the 00Z run show similar trends. Overpeck && .PREV DISCUSSION /Issued 639 PM CDT Tue Apr 23 2019/... .DISCUSSION... Some light rain have been falling around Southeast Texas today associated with weak disturbances moving across the area in the southwest flow aloft. Anticipating a break in this activity tonight for a majority of the area followed by a slight increase in rain chances during the day tomorrow. Much better shower and thunderstorm chances are still on track beginning early tomorrow evening across our western counties and then spreading eastward during the remaining evening and overnight hours across the remainder of the area as the upper low and associated cold front move slowly eastward across the state. Dynamics are still looking pretty good for possible strong/severe storms with this system. The primary severe weather threat still looks like hail, strong winds and lightning. Isolated tornadoes and locally heavy rainfall might be possible too. While a majority of activity should be east of our area by sunrise Thursday morning, the slow movement of the system might allow for some daytime heating related redevelopment during the day on Thursday. Everything should be off to our east Thursday evening with high pressure beginning to build into the state. Looking at a couple of coolish nights (Thursday night and Friday night) before the high moves off to our east and onshore winds come back to the area. While the end of the week and the weekend stay dry, lots of sunshine will help to boost afternoon high temperatures into the mid to possibly upper 80s. This forecast package has Monday dry followed by low rain chances back to the area beginning Tuesday. 42 .AVIATION [00Z TAF Issuance]... Big changes on the way, and this forecast mainly aims to sketch out the highlights. VFR currently across the majority of the area, but a couple are already leading the charge into MVFR that will occur tonight. Some may even briefly dip into high IFR around sunrise. Tomorrow, look for showers and eventually storms to push in from the northwest late this afternoon into the evening. Have begun to try to broadbrush that from IAH northward, and think that will be able to hold off until the 06Z cycle coastward of IAH. .MARINE... A fairly tight pressure gradient across the northern Gulf generated from a Mobile Bay High and lowering northwestern Texas pressures has maintained a moderate onshore wind. As the next storm system develops out west, the onshore pressure will remain tight enough to keep these regional Caution level winds in place through late tomorrow night. Other than some scattered showers and a rogue thunderstorm, local bay and Gulf weather will remain fairly benign through tomorrow night. As we approach the late Wednesday evening hours, the probabilities for rain and thunderstorms significantly increase going into the (overnight) early Thursday morning hours. Offshore winds behind a Thursday frontal passage will not be overly strong, briefly Caution level, at most. Sea state will remain elevated due to slightly higher period between Thursday morning`s storms and post-frontal winds through Friday morning. High pressure settles in over the weekend and settles both winds and sea state out to tranquil. Weak onshore winds will return by Saturday afternoon. 31 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 66 78 61 76 60 / 20 70 90 20 0 Houston (IAH) 67 79 65 79 61 / 20 30 90 30 0 Galveston (GLS) 70 75 68 77 67 / 10 20 90 50 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until midnight CDT tonight for the following zones: Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$ DISCUSSION... NEAR TERM...Overpeck
National Weather Service Jackson KY
1107 PM EDT Tue Apr 23 2019 .UPDATE... Issued at 1106 PM EDT TUE APR 23 2019 Hourly pops have been updated based on recent radar trends and trends in the convective allowing models. The threat for strong storms has ended, though a rumble or two of thunder will remain possible over the next few hours. UPDATE Issued at 821 PM EDT TUE APR 23 2019 Some minor adjustments have been made to pops based on recent radar trends and convective allowing models. The consensus of all this is that locations from around I 64 and north should experience numerous showers and some thunderstorms over the next few hours, but the activity should remain north of the Mountain Parkway for the most part. The potential for strong storms should diminish over the next hour or two as sunset passes. && .SHORT TERM...(This evening through Wednesday night) Issued at 425 PM EDT TUE APR 23 2019 19z sfc analysis shows a well defined cold front just northwest of the Ohio River. This nearby presence has helped to support breezy southwest winds of 10 to 15 mph across the area with gusts up to 25 mph. The more convective and mid level cloudiness associated with the front has only just now started to shift into the northern parts of the CWA. No showers or storms have developed along this boundary near our area so far this afternoon. However, initiation is expected momentarily as peak heating is taking its toll with CAPE starting to exceed 1000 J/kg along and ahead of the front. The sunshine and south winds supported temperatures climbing into the upper 70s to lower 80s through eastern Kentucky while dewpoints slipped into the middle to upper 40s, for most this afternoon. The models are mainly in good agreement aloft through the short term portion of the forecast depicting the split flow regime across the region. The northern one takes a compact trough through the eastern Great Lakes tonight with an impulse from the southern stream sliding over northern Kentucky north of a rather flat southeast ridge. This ridge builds a tad on Wednesday with an uptick in heights for eastern Kentucky as the main southern trough works further east in southern Texas. Additional energy will dampen out over the area Wednesday night while we await the southern stream trough`s arrival later in the week. The GFS, ECMWF, and CMC are faster bringing this low east than the laggard and stronger NAM - though this difference does not seem to manifest itself downstream, at least through Thursday morning. Given the limited model spread for the bulk of the time have favored a blend as a starting point with a lean toward the HRRR and NAM12 for details. Sensible weather will feature the convection and storms yet to develop along the front sliding into our northern counties this evening. A few of these could become strong with gusty winds, CG lightning, and heavy rain the main threat. The boundary will then settle over the area tonight as the instability wanes and convection tamps down. With the slight build in heights aloft on Wednesday expect the boundary to be slow to initiate any renewed convection of note - though by mid afternoon we should see that development with thunder a possibility, but not as likely as this evening given more limited instability and weaker mid levels. The risk of convection continues into the night with the northern fetches more favored than the south - and a better chance for heavier rains through the entirety of the short term. Used the CONSShort and ShortBlend as the starting point for all the grids through the period with little adjustments to temperatures aside from some near term extra cooling in the valleys with sunset - outside of the convection areas in the north. As for PoPs, have leaned on the high res CAMs to adjust them this evening with the NAM12 the guide later on - in this manner the diurnal trends where enhanced and more dominant than implied by the blends. .LONG TERM...(Thursday through Tuesday) Issued at 300 PM EDT TUE APR 23 2019 The latest model suggests that we will see three weather systems of note in the extended period. The latest data has a slow moving area of low pressure moving across the Tennessee Valley region from Thursday through the start of the upcoming weekend. A second weaker area of low pressure is also forecast to move across the Great Lakes region during the same time frame. A cold front trailing from the northern system is then forecast to interact with the northern fringe of the southern stream system. The combined moisture and energy from both systems is then forecast to bring widespread rain showers and a few thunderstorms to the area Thursday and Friday. The data then suggests that we will see a brief lull in the from late Friday through late Saturday, as a weak area of high pressure settles over the area. After that, a third weak and faster moving weather system is then forecast to move through the area from late Saturday through late in the day on Sunday. The weekend system will likely only produce general rain showers as it moves through. At the very end of the period the models are trying to push yet another area of low pressure across our area Monday night. Since this system is being forecast so far out in the period, we will take it with a grain of salt until the models come into better agreement. Temperatures in the extended will be all over the place, with some days seeing above normal highs and lows and other periods with below normal readings. The warmest highs are expected on Monday and Tuesday, with max readings in the upper 70s and lower 80s on tap on those two days. The coolest day should be Sunday, when highs are forecast to range from the mid 60s in the north to the lower 70s in the south. The rest of the extended period should see normal highs. Nightly lows are forecast to be in the 40s and 50s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 815 PM EDT TUE APR 23 2019 Some convection is occurring across the OH Valley region in advance of a slow moving cold front. This activity could affect locations as far south as JKL and SJS, but SYM will have the highest chance for a thunderstorm. With this, we have continued with a few hours of VCTs for SYM only. As the boundary sags into the area, ceilings should lower into the MVFR range across the northern half to two thirds of the area between 6Z and 12Z before improving back into the VFR range in most locations through around 18Z. Winds should generally be 10KT or less through the period and become more or less light and variable as the front stalls out over the area. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP
Area Forecast Discussion
National Weather Service Marquette MI
628 PM EDT Tue Apr 23 2019 .SHORT TERM...(This evening through Wednesday) Issued at 411 PM EDT TUE APR 23 2019 Water vapor imagery and RAP analysis show a trof moving e from the Great Lakes region in an otherwise zonally oriented flow across the northern CONUS/southern Canada. Within this flow, shortwave moving across southern British Columbia will be the next feature of interest during the short term. In the wake of the Great Lakes trof, much drier air flowing into the Upper Great Lakes has resulted in clouds clearing out from w to e today. However, some stratus/stratocu still lingers over the eastern fcst area. Under sunny skies, temps have risen into the 50s (near 60F in a few spots) s central and interior w. Northerly wind off Lake Superior is keeping conditions cool, upper 30s/lwr 40s, near the lake. It`s especially chilly in n central and eastern Upper MI due to a blustery n wind in those areas. A quiet night is expected tonight as sfc high pres ridge, currently extending from Hudson Bay across western Lake Superior to the central Plains, drifts e across the area. Mainly clear skies initially tonight will give way to some high clouds spreading across the area as upstream waa regime spreads downsteam. Precipitable water will be increasing from the w during the night, and along with some high cloudiness, it won`t be an ideal radiational cooling night. Still, with light/calm wind under passing sfc high pres ridge, leaned fcst to the low side of guidance tonight. Temps should fall to the mid 20s in the traditional cold spots in the interior central and e. Earlier arrival of high clouds/higher precipitable water and development of light se/s return flow will keep the far w warmest, upper 30s/around 40F in the downslope areas near Lake Superior. Low-level jet of 30-40kt in response to the approaching shortwave will shift e over western Upper MI during the day on Wed. Since theta-e advection is weak, have doubts on whether any -shra will occur, especially in light of the dry air that lingers in the low levels blo 5kft. For now, have only included schc pops over the nw fcst area. Otherwise, will be a breezy, warmer day. Temps this aftn out across the Dakotas are pushing thru the 60s with some lwr 70s showing up as of 20z. Mid/upper 60s should be common for high tmeps across the w half of Upper MI on Wed. Might see a few spots reach 70F. Will be cooler over the e with southerly wind up Lake MI. Temps will range down to the 40s lakeside. .LONG TERM...(Wednesday night through Tuesday) Issued at 409 PM EDT TUE APR 23 2019 Continued southerly/southwesterly flow ahead of a shortwave trough combined with cloudy conditions Wednesday night will keep temperatures in the low to mid 40s. Some light showers will move across from west to east, exiting before midday Thursday. As conditions dry out and clouds clear, another nice spring day will be in store with highs in the upper 50s east to mid 60s interior west. A few spots that still have snow on the ground in the Keweenaw and Michigamme Highlands will continue to melt off and runoff into rivers will continue. Another trough will dig in from the north on Thursday night into Friday that will bring additional cloud cover, but the air mass looks to be too dry to produce more than a few spotty showers, mainly over the east. It will usher in a cooler airmass for the weekend, with highs Saturday and Sunday topping out in the 40s. A stronger system with a notable surface low is expected to pass to our south Saturday evening and night. There is some discrepancy in the strength and track of this system, but it is possible that areas near the WI border will experience additional shower activity, and perhaps even a few snow showers overnight. Following that, the models continue to diverge. The EC would bring about a quarter inch of QPF on Monday ahead of a trough that is not resolved in the CMC/GFS or indicated in any of the ensembles, so for now POPs remain low. A better signal for rainfall comes at the end of the forecast period on Tuesday night, but there is plenty of time to work out the details there. Ideally, area rivers will have some time to recede before we get any more heavy precip events. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 628 PM EDT TUE APR 23 2019 VFR conditions will prevail at all sites thru this fcst period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 411 PM EDT TUE APR 23 2019 Sfc high pres ridge currently extending ne to sw across western Lake Superior will drift e tonight. As it does so, winds will remain light, under 15kt, over the western part of the lake. Over the eastern part of the lake, nnw winds around 20kt will fall off to under 10kt tonight. Ahead of an approaching cold front, expect s to se winds generally in the 10-20kt range on Wed, strongest over the e half. Winds may increase a bit more over the e half Wed night prior to passage of the cold front. Behind the front, westerly winds should be mostly under 20kt on Thu. In the wake of another passing cold front, w to nw winds up to 15-25kt are expected on Fri, potentially up to 30kt over the e half. Winds should mostly be under 20kt over the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...KCW AVIATION...07 MARINE...Rolfson
Area Forecast Discussion
National Weather Service Reno NV
323 PM PDT Tue Apr 23 2019 .SYNOPSIS... Warm days, cool to chilly nights, and dry conditions are expected this week for northeast California and western Nevada. Warmer temperatures will lead to increases in cold and swift flows for area streams, with minor flooding possible for agricultural areas in the Carson Valley. Isolated showers and thunderstorms are possible Wednesday and Thursday afternoon and evening. && .SHORT TERM... The main change to the forecast through Friday was to add isolated showers and thunderstorms to eastern California and far western Nevada Wednesday afternoon and evening. Above to well above average temperatures will prevail for northeast California, the Sierra, and western Nevada this week under an upper ridge. Stronger east to northeast winds over high Sierra ridges last night into this morning have diminished considerably this afternoon as the upper ridge builds overhead. Precipitation chances still don`t look great for Wednesday/Thursday, but cannot rule out isolated afternoon/evening thunderstorms. Wednesday may have the best shot with well above average temperatures and light convergence (weak zephyr) over and just east of the Sierra by late afternoon to foster deeper moist convection. The NAM has been consistent showing this although it is a bit at odds with the high-res HRRR which shows convection kicking well off the Sierra crest (into western NV). Thursday, stronger westerly flow is expected with less convergence outside of the Lassen Convergence Zone (north of Susanville) and eastern Mono County and Mineral County. Friday, chances for showers wane further as slight cooling (more stable) and much weaker convergence under northwest flow inhibits deep convection. We have left a slight chance of showers downwind of Lassen Peak with leftover shallow moisture possibly bringing a brief shower or two. -Snyder .LONG TERM...Saturday into the beginning of May... The pattern for this weekend into the beginning of next week looks rather stagnant with the jet stream draped over the northern half of the country allowing broad, weak areas of low pressure to drop southward. Saturday looks to be the nicer day of the weekend as a shortwave ridge develops over the U.S. Southwest leading to warm, above average temperatures, a partly cloudy sky, and light afternoon breezes. These conditions will not last long as a cut-off low pressure system makes its way towards the southern California coast by Sunday afternoon. As the system moves closer inland, it will begin to interact with a more broader area of low pressure over the Pacific NW. According to the recent long range deterministic model runs, cloud cover looks to increase over the Sierra and western Nevada region with a cool down in temperatures likely. Westerly winds should also pick up by Sunday afternoon across the region with the chance of some rain showers developing over areas mainly south of I-80. Once we begin the new work week, these active weather conditions look likely to remain with us as the cut-off low passing to our southeast becomes absorbed by the broader area of low pressure to our north. No major impacts are expected with a persistent west-northwest wind, isolated rain showers, and average high/low temperatures for this time of year. As we begin the month of May, the GEFS & EPS show weak troughing over the West Coast with no significant warm up anticipated for the next week or two. Sounds like typical spring weather to me! -LaGuardia && .AVIATION... VFR conditions and overall light winds will continue through Wednesday as high pressure builds over the Sierra and western NV. There is a very low (~5-10%) chance for a shower or thunderstorm for terminals across eastern California and far western Nevada after 2-3 PM (21-22Z) Wednesday. Any thunderstorms could bring outflow winds to 30 kts, a couple lightning strikes, and brief -RA. Expect breezier conditions Thursday and Friday, with a few showers or even an isolated thunderstorm for Thursday north of KSVE and in Mineral County/near KHTH. -Snyder && .HYDROLOGY... Warmer daytime and overnight temperatures combined with lots of sunshine and long days will lead to the first large pulse of melt for the low to mid elevation snowpack. Flows are expected to be high, cold and fast in snow-fed rivers and streams throughout the area. Most rivers and streams are expected to stay significantly below flood stages; however, the West Fork of the Carson River through Carson Valley is forecast to be very near flood stage Thursday night into Friday morning and again Friday night into Saturday morning. With this in mind, we have issued a flood watch for the West Fork of the Carson River for this period. Any increase in observed or forecast temperatures will likely result in minor flooding in this area. High flows are expected to continue into the weekend. Still, the highest flows are still beyond the forecast window for most rivers and streams draining high elevation terrain, especially from the Lake Tahoe area south through Mono County. Remember: snowmelt peaks typically occur in the evening and overnight hours in the higher portions of the basin while peaks are more likely in the early morning hours in the lower portions of the basin. -Bardsley && .REV Watches/Warnings/Advisories... NV...Flood Watch from Thursday evening through Saturday morning for portions of the Carson Valley. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Shreveport LA
1010 PM CDT Tue Apr 23 2019 .SHORT TERM.../Tonight/ An organized area of convection over N TX has shown signs of slowly building E this evening, in an area of mid-level forcing ahead of a deepening closed low sinking slowly S across NW old MX. This is occurring near and just SE of a slow moving sfc front extending from near a COM, to MWL, to N of a GYI, to AQR and MLC line as of 03Z. The short term progs are in good agreement with this bndry moving very little overnight, and may actually be convectively reinforced SE a bit more, with a SSE low level flow maintaining low level convergence and hence the convection overnight near this bndry, as broad diffluence aloft persists ahead of the deepening closed low to the SW. The ongoing convection looks to eventually build NE into portions of extreme NE TX/SE OK/possibly into adjacent sections of SW AR mainly after midnight tonight, as large scale forcing expands NE ahead of the front and NE ejecting shortwave energy. Fortunately, MLCapes continue to diminish further NE away from the current convection into NE TX/SE OK, thus the convection should continue to gradually weaken as it expands ENE into these areas later tonight. Given the good agreement with the latest HRRR and 00Z NAM/18Z GFS, have raised pops to likely across the far NW zones, tapering pops to chance to near/N of the I-20 corridor of E TX into much of SW AR. Also made a few minor adjustments to the forecast min temps, bumping temps up a degree or so across E TX/SW AR/NW LA where S winds and the thickening convective debris should limit the temp fall. Convection coverage should increase throughout the morning Wednesday over E TX once better large scale forcing increases ahead of the upper low as it emerges out over WCntrl TX. Zone update already out...grids will be available shortly. 15 && .PREV DISCUSSION... /issued 732 PM CDT Tue Apr 23 2019/ AVIATION... For the 24/00Z TAF period, VFR conditions are prevailing to begin this period as cu field has scattered out this afternoon. Light southerly flow will continue and aid in the redevelopment of lower cigs after midnight through Wednesday, mainly in the MVFR range with some intermittent IFR cigs possible around daybreak. Cigs will be slow to lift through the morning with increasing chances for convection through the afternoon hours ahead of an upper level trough pivoting across Texas. For now, have only included VCTS in this TAF cycle during Thursday afternoon across our east Texas terminals as well as SHV/TXK. Otherwise, look for MVFR/low VFR cigs to prevail during the latter half of the period ending at 25/00Z. /19/ && .PRELIMINARY POINT TEMPS/POPS... SHV 63 76 62 75 / 10 50 90 60 MLU 61 78 64 75 / 5 20 50 70 DEQ 64 73 59 72 / 60 60 90 70 TXK 62 73 60 73 / 40 70 90 60 ELD 61 77 63 73 / 10 20 70 60 TYR 64 72 60 74 / 30 80 90 50 GGG 63 74 60 75 / 20 70 90 50 LFK 64 78 62 77 / 10 60 90 50 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 15/19