Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/28/17


Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
526 PM MDT Mon Mar 27 2017 .AVIATION... 00Z TAF CYCLE Upper low evolving over UT and nrn AZ at 23Z will slide to the east and southeast and into wrn and nrn NM around 28/12Z. Unsettled wx with lower elevation rain and high mtn snow showers along with isold tstms will increase across the region with occasional mt obscurations. Prior to 06Z, showers will more likely produce gusty variable winds to around 35kt rather than precipitation as the lower levels of the atmosphere are initially rather dry. West to northwest winds will strengthen aft 28/18Z as the surface low intensifies over east central NM, although the exact track and location of both the upper and surface lows are not being well forecasted by the models. && .PREV DISCUSSION...327 PM MDT Mon Mar 27 2017... .SYNOPSIS... The storm track remains active across New Mexico this week. A pair of systems through the weekend will bring periods of rain and high elevation snow. The main impacts from the first system will be across northeast New Mexico Tuesday night through Wednesday morning with potential for heavy snow across the Sangre de Cristo Mountains and Raton Pass. Good lower elevation rains will be possible for much of the plains. Another system may impact New Mexico Friday through the weekend with another round of valley rains and mountain snows. Temperatures will generally be below normal thanks to the increase in cloud cover and precipitation. && .DISCUSSION... A difficult forecast this afternoon due to models diverging on the track of the next two storm systems. The first storm system is already impacting NM as showers have developed across the northwest. The HRRR and GFS have been showing a band of precip focusing across the ABQ and SAF metro areas this evening and overnight, but the latest HRRR may be slightly shifting eastward over the higher terrain of the Sandia/Manzanos and Sangres. Nonetheless, should be rather light with snow levels around 8000 feet. Additionally, these same models develop another band of precip across the eastern plains toward sunrise in an area of weak surface convergence and on the nose of the upper jet. Questions arise tomorrow regarding the track of the system. The GFS takes the center of the low across northern NM and by 06Z Wed, centers the low over NE NM. Meanwhile, the ECMWF dives the low southeastward and by 06Z Wed, centers the low over southeast NM. The NAM low is closer to the GFS position, while the GEM is closer to the ECMWF. All ensemble means also favor their respective operational model, so not much help there. The 120-130kt jet on the back side of the system suggests that the EC/GEM may be onto something. The differences between the low position will have significant impacts on where precipitation will fall. The GFS outcome will favor precipitation across the northern mts and northeast NM, whereas the ECMWF will favor precip across much of the eastern plains. In either case, the snow levels will be low enough (~7500-8000ft) for potentially significant snow amounts across the Sangre de Cristo Mtns and the Raton Ridge. Thus will hoist a winter storm watch for these areas starting at noon Tuesday. At lower elevations, rain will be the p-type. Periods of heavy snow and moderate rain are possible which may reduce visibilities. Precipitation will wane Wednesday evening, then shortwave ridging will move over the area on Thursday. Thursday`s temperatures will warm 5-15 degrees over Wednesday`s highs. The break will be short-lived as another storm system will be impacting NM Friday into the weekend. Initially models agree on the track of this system, shifting the low over the Four Corners on Friday night. Thereafter, however, the EC quickly scoots the low across northern NM, where the GFS dives the low southward along the AZ/NM border, then eastward along the Mexico border. Thus, significant differences in precipitation potential and timing. Too early to say which model has a better handle on this system. Another system may be in store early next week. Needless to say, this is a low confidence forecast this afternoon. 34 && .FIRE WEATHER... An unsettled weather period is still on target beginning tonight over NM as an upper level low takes shape over the area and moves slowly east/southeast through Wednesday. Scattered valley rain and high terrain snow will gradually develop over the state tonight then spread into most of the region Tuesday. A few storms are possible just about anywhere. Wetting precip is possible for central and western NM with greater potential for moderate to heavy precip for the eastern plains Wednesday and Wednesday night. The stronger west winds that were advertised Tuesday are now more into southern NM as the parent upper wave is trending farther south on latest guidance. Meanwhile, temperatures will become cold enough for snow, possibly heavy, over the Sangre de Cristo Mts and the Raton Ridge. Winds will become northerly all areas as the low exits into the plains. Flow aloft will become more zonal Thursday with drier and warmer air shifting into NM. Spotty marginal critical conditions are likely along and south of Highway 60. Winds will remain elevated over ridge tops Thursday night ahead of the next upper wave. Model guidance is really falling out of agreement with this next system which shows a slower and farther northwest placement initially late Friday. As a result, a dry slot with deep mixing and unstable conditions focuses over the southeastern third of the area. Critical conditions are possible Friday afternoon for the east central and southeast plains and perhaps the southern fringes of the middle Rio Grande Valley and the south central highlands. Any critical conditions will end from west to east as the upper wave moves into NM Friday night through Sunday. As noted, confidence is decreasing on the timing and placement of the overall feature but regardless a cooler period with higher humidity, cloud cover, and at least scattered showers is likely for the weekend. Guyer && .ABQ WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Tuesday afternoon through Wednesday afternoon for the following zones... NMZ512>515-527. && $$
Area Forecast Discussion
National Weather Service Bismarck ND
918 PM CDT Mon Mar 27 2017 .UPDATE... Issued at 906 PM CDT Mon Mar 27 2017 Dense fog has formed over many portions of northern North Dakota so have gone ahead and issued a dense fog advisory. Latest HRRR seems to have been working out pretty well on the timing of the leading edge of the dense fog, though has not been doing as well with the back side of the fog. Past and current runs have been clearing out the backside, but satellite shows that fog over southern Manitoba has been reluctant go to away. Anyways, will keep advisory going through mid-morning Tuesday, and if clearing does actually develop over the northeast later we can always trim back on the advisory. UPDATE Issued at 627 PM CDT Mon Mar 27 2017 For early evening update have advanced timing a bit on the fog setting in over northern locations as it has already pushed into the Minot area. As for precipitation, convective showers over central North Dakota appear to be on the decrease, so will let chances diminish through the early evening. Next round of light precipitation trying to push into northwestern parts of the area at this time. A look at latest soundings still shows the potential for a little snow/rain mix over the far northwest. Over the far north central a little freezing rain/sleet will not be out of the question, although chances for this remains quite low. && .SHORT TERM...(This evening through Tuesday) Issued at 334 PM CDT Mon Mar 27 2017 Forecast challenges in the short term period will be stratus and fog coverage tonight & tomorrow, along with precipitation chances/placement. Currently, embedded mid level impulse moving easterly across western and central North Dakota combining with weak instability and an easterly upslope flow to result in a scattered showers along a west to east orientated stationary front from eastern MT through McKenzie-central Dunn-Mercer-southern McLean/Sheridan counties. Expect this activity to linger through the afternoon/early evening before dissipating. Stratus and areas of fog remain over my north central and far northeast. Another area of light precipitation will move across northwestern and far north central ND tonight associated with another embedded wave now moving into northeastern Montana. Otherwise the main concern tonight will be stratus and fog. High res models have persistently shown the low cigs/fog across the north developing south with time tonight with the exception of the southwest on the other side of the frontal zone. Also, dry air associated with high pressure over northern/central Manitoba will eventually work into the area tonight eroding the areas of fog over my northeastern counties. Basically followed the HRRR guidance for placement of stratus and fog which develops a northwest to southeast orientated area from northwest ND to across the James River Valley. Fog will likely linger into Tuesday morning. Another mild day Tuesday with decent chances for rain over southwestern ND. Mainly dry central and east. .LONG TERM...(Tuesday night through Monday) Issued at 334 PM CDT Mon Mar 27 2017 Mild/above normal temperatures will continue through the period. Best chance for precipitation looks to be late Thursday night- Friday-Friday night when a northern stream S/WV trough pushes across the Northern Plains. Otherwise mainly dry conditions will prevail. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 627 PM CDT Mon Mar 27 2017 Widespread IFR/LIFR conditions in low cigs and fog are to continue developing over many parts of northwest into central North Dakota, particularly along and north of a line from KMOT to KJMS. Remaining locations will see areas of MVFR with localized IFR conditions. Southern locations will see improvement to VFR by mid-day Tuesday, while northern locations may improve to MVFR with localized IFR cigs. && .BIS WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 10 AM CDT Tuesday for NDZ001>005- 010>013-021>023-025. && $$ UPDATE...JJS SHORT TERM...NH LONG TERM...NH AVIATION...JJS
Area Forecast Discussion
National Weather Service Des Moines IA
1001 PM CDT Mon Mar 27 2017 .UPDATE... Issued at 943 PM CDT Mon Mar 27 2017 Have updated short term forecast to increase fog wording across the northern tier of counties in our CWA. Strong clearing taking place as subsidence and drier air entrained into northern Iowa from high pressure across northern Minnesota. High confidence winds will be less than 5 kts overnight. Sfc dwpt depressions already less than 4 degrees across much of northern Iowa. Monday evening RAP has been handling clearing the best, and HRRR starting to join the game. Looking at fog beginning to develop between 04 and 06z...possibly reaching Dense Fog Advisory criteria of sustained, less than 1/4 of a mile from Kossuth county to Cerro Gordo county and northward. Vsby reductions also possible down to Waterloo... but as of now, vsbys look like they will stay in the 3 mile or above range as clearing may not make it that far south/SE. Dense Fog Advisory potential is medium-high. Will continue to monitor closely. && .SHORT TERM.../Tonight through Tuesday/ Issued at 355 PM CDT Mon Mar 27 2017 The low pressure system that helped continue the abundance of cloud cover and showers across the south moved off to Illinois, being replaced by a weak inverted high pressure ridge moving into Western Iowa. Clearing/erosion of western/northwestern edge of the cloud deck proved slower than overnight hi-res guidance suggested, resulting in continued blanketed cloud cover over the state and keeping highs down in the upper 40s/low 50s. Hi-res guidance has continued to appear overly aggressive in clearing out cloud cover over northern and western Iowa, especially taking into consideration performance through the day today. Have thusly kept with generally overcast skies across the CWA with low level moisture remaining and only mid-upper level drying to occur. While cloud cover will remain overnight limiting dense fog potential, with the ridge passing through have introduced patchy fog across a fair amount of the CWA, and especially the north where winds will be lightest. While winds will be easterly tomorrow, with the thinner cloud deck temperatures should be able to jump a few more degrees into the mid 50s in most locations. A bit more erosion of the northern/northwestern edge of the cloud deck will likely occur as well Tuesday before the next system once again keeps the region blanketed in cloud cover. .LONG TERM.../Tuesday night through Monday/ Issued at 355 PM CDT Mon Mar 27 2017 Primary focus in the long term will continue to be on the relatively active weather pattern...with cool and wet conditions continuing over Iowa and the central Midwest. Tuesday Night thru Thursday Night: Forecast Confidence = Medium/High The next in the wave train of low pressure systems is expected to slowly track across the southern plains from Tuesday night into early Friday. While the most robust low level moisture and potential for severe wx will likely remain well south of Iowa...persistent WAA/isentropic upglide and deep moisture convergence will lead to widespread precipitation development by early Wednesday morning. Periods of deformation zone precipitation will then continue off and on right into early Friday. While most of the precip will likely fall as rain...kept a mention of a rain/snow mix across far northern Iowa on early Thursday morning. Little or no snow accumulation expected. Total rainfall in this period will likely range from 1-2" across the southern half of the state...with 0.25" to 1.0" across the north. Did not see much river response with the weekend rainfall...but with soils more saturated now...will need to keep an eye on river trends by midweek. With overcast and rainy conditions...highs on Wed/Thu are expected to be a bit below climo avgs...generally in the 40s to perhaps the lower 50s south. Overall...rather dreary and raw. Friday and Friday Night: Forecast Confidence = Medium A brief lull in the action is expected on Friday as weak high pressure builds into the region. However...model soundings and time sections still show considerable RH/saturation in the lower levels...thus expecting partly to mostly cloudy conditions to continue. If we can eek out a little sun...highs expected to rise a few degrees into upper 40s to lower 50s on Friday. Saturday thru Monday: Forecast Confidence = Low Higher uncertainty in the forecast late in the period as the deterministic and ensemble solutions track yet another closed low across the southern U.S. Have maintained chance PoPs in the forecast for Saturday into Sunday for now...but the overall trend of the solutions have been slower and further south with this low. Plenty of time to fine tune this period in the upcoming days. && .AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/ Issued at 635 PM CDT Mon Mar 27 2017 Made notable changes for KMCW, KFOD, and KALO by reducing vsbys overnight tonight. If clearing becomes more pronounced, especially KMCW and possibly KFOD may reach 1/2 SM vsbys or less. Fog should lift by 15z Tue. CIGs likely to hover near 3000 ft, meaning it will be difficult to pin down MVFR vs VFR with confidence for Tuesday afternoon/evening until 12Z and 18Z Tue TAF packages. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Kotenberg SHORT TERM...Curtis LONG TERM...Small AVIATION...Kotenberg
Area Forecast Discussion
National Weather Service Hastings NE
923 PM CDT Mon Mar 27 2017 .UPDATE... Issued at 903 PM CDT Mon Mar 27 2017 Updated the forecast for tonight to bring in fog a bit earlier and extend farther east to include all of tri-cities. I suspect a portion of the CWA may really tank late tonight as both the HRRR and SREF indicate that this is a distinct possibility as we will be on the west edge of stratus and we cleared late in the day for much of the CWA. HSI even temporarily dipped to 2 1/2SM earlier in the afternoon when sun broke out and warmed a soaked ground. Will monitor to see if it is prudent to go any further with fog potential. && .SHORT TERM...(This evening through Tuesday) Issued at 319 PM CDT Mon Mar 27 2017 Current stratus has been slow to erode this afternoon, but the western and northern areas have seen a little sun this afternoon. The southeast may struggle to get much sun unless it erodes a little faster. The clouds have also impacted temperatures this afternoon and will likely cool things of a little. With the stratus not going away, there will likely be some more stratus and some fog tonight. With the surface high gradually moving to the east, there will be a more easterly component to the winds this evening and tonight. Late tonight there will be an upper level wave that approaches from an upper low on the high plains. Some light rain should move into the western part of the forecast area late tonight. On Tuesday, the upper low continues to move slowly into the central and southern plains. The chance of precipitation spreads to the east and much of the forecast area should get some precipitation by late afternoon. .LONG TERM...(Tuesday night through Monday) Issued at 319 PM CDT Mon Mar 27 2017 The upper level low will move to the east Tuesday night through Thursday and is expected to continue to bring chances for precipitation to the area. The best chances will be from Tuesday night through Wednesday night. Precipitation should be fairly widespread and there should be some beneficial rain for most. By Thursday, the upper low is moving to the east and precipitation should move out of the area during the afternoon. Thursday night and Friday there is a weak upper level ridge moving through the area and a surface high drifts through. This period should be dry, even if there are some clouds around the area. Friday night through Saturday night there is another upper level low that moves out of the Rockies and through the central and southern plains. The models have some differences in them that could lead to some changes in the weather. The ECMWF has more of an open wave that moves through a little faster than the GFS with a cut off low in the southern plains that is slower. There are still some good chances for some precipitation, but with the model differences, there is a little uncertainty. That uncertainty continues into Sunday through Monday. Currently have followed more of the ECMWF with the open wave that gives a break during the day on Sunday, then brings in another wave Monday. Through the period, temperatures will be a few degrees either side of normal or this time of year. A couple of the nights may be a little on the cooler side and there could be a mix of snow. Have tried to keep this to a minimum since it has been so warm it may be a bit of a challenge to get much snow. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday evening) Issued at 657 PM CDT Mon Mar 27 2017 Biggest issue will be chance of fog. Being on the west edge of stratus and light wind will put us in a position of potential lower fog than in the forecast. This will be monitored closely, and visibility may need lowered, despite some models not picking up on any dense fog. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Heinlein SHORT TERM...JCB LONG TERM...JCB AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Green Bay WI
633 PM CDT Mon Mar 27 2017 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Tuesday Issued at 244 PM CDT Mon Mar 27 2017 The latest RAP analysis and satellite/radar imagery show a shortwave trough moving over northeast Minnesota and western Lake Superior early this afternoon. Scattered showers continue to develop ahead of the shortwave over north-central and far northeast WI. Think will see the showers continue to develop through the rest of the afternoon. But drier air lies just to the west, with the leading edge of the clearing approaching Rice Lake and Hayward. Meanwhile, high pressure is building south over Manitoba. Forecast concerns include shower potential extending into this evening, followed by cloud trends and fog potential. Tonight...Shortwave trough will continue to move northeast over Lake Superior tonight. Mid-level moisture will depart with the shortwave early in the evening, so think the light shower activity will have mostly departed by 00z. Attention then turns to cloud trends. Nearly all guidance shows drying coming in from the north as Canadian high pressure builds into the region. How quickly that occurs varies from model to model, and generally sided with the slower RAP, which was not that different from the previous forecast. If clearing does occur late in the evening into the early overnight across northern WI, then there is potential for dense fog/low stratus to redevelop as temperatures cool under light winds. With the late departure of the clouds over central and east-central WI, however, do not think will see those same trends further south. Low temps falling into the mid 20s north to the mid 30s south. Tuesday...High pressure will continue to build south into the region. Any lingering low clouds and fog will look to dissipate by mid-morning as dry air gets mixed down from aloft. Then should see ample sunshine for the rest of the day. Quite a difference of 925mb temps in the models, but trended warmer towards the ecmwf, since think bias corrected grids may be influenced from the cooler/wetter pattern of the past few days. Highs ranging from the mid 40s near the lake to the mid 50s over central WI. .LONG TERM...Tuesday Night Through Monday Issued at 244 PM CDT Mon Mar 27 2017 Quiet weather to start the long term, then a low pressure system will bring precip chances to the area Thursday into Friday, but the 12z/27 models have shifted south, keeping the bulk of the precip south of the area. However, questions still remain if this shift is temporary or if it will stick. Near normal temperatures are expected Wed-Fri then above normal readings return for the weekend. Dry conditions are expected Tuesday night into Wednesday as surface high pressure slides across Ontario and mid-upper level ridging pushes across the Great Lakes. Mostly clear skies are expected to start Tuesday night, but mid-upper clouds will be approaching as moisture increases ahead of the next system, so not expecting much sunshine on Wednesday as mid clouds are expected with highs mainly in the 40s. Attention turns to the system ejecting out of the southwest U.S. on Wednesday. GFS remains farthest south with the track and associated precip, and now has the system completely missing the area. Canadian trended south on its 12z/27 run, with most of central and north central WI missing out on any significant precip, but still brings up to 0.75" of liquid to east central WI Thursday and Thursday night (seems to be the outlier now). The 12z/27 ECMWF trended to the south as well, keeping the swath of heavier precip just to our south across southern WI and only a tenth or two of liquid over far east central WI. Models are trending south, but a flip- flop is always possible with these systems so confidence on how this system will play out remains on the low- medium side. Bottom line...the chances for getting any accumulating snow and/or heavy precip looks to be diminishing at this point, due to a southern shift to the system keeping the bulk of the precip over southern WI. Plus, ground temps will be pretty warm, with much/all of the frost out of the ground across east central WI thanks to the recent rain and above freezing temps. Would need to get into the heavy precip to cool the boundary layer sufficiently for snow and to get anything to stick on the ground. Will reduce POPs significantly across central and north central WI and keep nearly the entire area dry on Friday. Canadian shows lingering moisture in the cyclonic which would keep a few showers around Friday night into Saturday morning, but other models are dry. Will lean toward the drier models. A mid- level shortwave will cross the northern Great Lakes on Saturday, with a secondary shortwave right on its heels for Sunday. Both could touch of a few showers, but at the surface weak high pressure will be in place, plus there will be no deep moisture to work with so activity is expected to be isolated at best. In addition, not much skill in trying to time these fast moving features this far out. Will keep POPs on the low side or out of the forecast all together until the picture gets a little clearer. && .AVIATION...for 00Z TAF Issuance Issued at 631 PM CDT Mon Mar 27 2017 MVFR ceilings clearing from northwest to southeast overnight, though low clouds could form where skies are clear for several hours. So look for some clearing this evening but possible areas of low clouds late tonight where skies do clear. Skies should become mostly clear by 15z Tuesday with good flying weather Tuesday afternoon and evening. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Bersch AVIATION.......RDM
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
205 PM PDT Mon Mar 27 2017 .SYNOPSIS...High pressure will build over the region tonight through Wednesday before another fast moving a potentially windy storm system drops into the Great Basin on Thursday and Friday. && .DISCUSSION...Northwest flow continues over the region with strong and gusty winds over the Kern County Mountains and desert and to a lesser degree the west side of the San Joaquin Valley. Gusts thus far have been as high as 64 mph at Cache Creek Weigh station on Highway 58 and 57 mph at California City. Current surface pressure gradient is 9.4 millibars between Bakersfield and China Lake and 16 mb from San Francisco and Las Vegas. Latest HRRR model keeps gusts to over 45 knots going in the desert through around 8 pm, thus the advisory and high wind warning will remain in place. Winds subside quickly overnight per the same model. Given the continued northwest flow into the Grapevine area, pops will remain in place for upslope drizzle or light rain mainly along San Joaquin Valley facing slopes through the evening. Models are in good agreement in building a ridge over the region Tuesday and Wednesday for a warming and drying trend along with much lighter winds. The flow will become easterly over the Kern County with some light offshore or pseudo Santa Ana winds over the Tehachapi`s. The next system is progged to push southeast into the Great Basin Thursday afternoon and evening bringing a returned threat of strong winds over the Kern County mountains and desert and some quick hitting light precipitation in the Sierra. More ridging follows for the weekend with models bringing a very similar tracked low into the region on Monday. All in all a roller coaster ridge of fast moving lows and ridges. && .AVIATION... In the San Joaquin Valley and Grapevine region widespread mvfr and local ifr in clouds and drizzle along south end of valley through 12z otherwise VFR over entire area through 00z Wednesday. Gusty winds to 50kts possible over Kern County mountain passes and desert through 06z. && .AIR QUALITY ISSUES... None. && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.php for additional information an/or to provide feedback. && .HNX Watches/Warnings/Advisories... High Wind Warning until 11 PM PDT this evening CAZ095-098-099. Wind Advisory until 8 PM PDT this evening CAZ089>091. && $$ public...Dudley avn/fw...Dudley synopsis...Dudley weather.gov/hanford
Area Forecast Discussion
National Weather Service Wilmington NC
852 PM EDT Mon Mar 27 2017 .SYNOPSIS... Changeable conditions will persist for the next several days. There is a chance of showers and possibly thunderstorms Tuesday and again Friday and early Saturday. The weekend should be dry with an increasing chance of showers early next week. && .NEAR TERM /THROUGH TUESDAY/... As of 800 PM Monday...Have followed closely to the HRRR model for pcpn this evening which pretty much has it dissipating by now in conjunction with what the latest KLTX 88D is displaying attm. However, both the RAP and HRRR are somewhat in unison in re-developing pcpn just southwest of the ILM CWA during the pre-dawn hrs and pushes northeast and affects the SW thru W portions of the ILM CWA toward daybreak Tue. Have re-vamped POPs to low chance in these areas. Have continued the increase in pops for showers and tstms during Tue morning ahead of the approaching dynamics aloft. The instability avbl for thunder will be borderline but given time of day and marginal being advertised by SPC for the ILM NC CWA, have kept thunder included thruout the FA. Tonights lows in the 50s to near 60 needed very little tweaking. Although the official surf zone forecast season has not started yet. It bares to mention that local beaches will see some increase to rip current activity during Tuesday. This a result of a healthy SE ground swell affecting the local waters and increasing the surf. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Mid level ridging moving slowly across the Tennessee Valley will be the main player through the short term period. This will allow high pressure to migrate from the Great Lakes region into a cold air damming scenario by early Thursday. With a cold front moving offshore early in the period, pops will not be an issue through the period. Expect mostly sunny skies Wednesday with some low level cloudiness developing in with the wedge early Thursday. Expect another warm day Wednesday with highs possibly reaching and eclipsing 80 degrees before the cool down Thursday. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 AM Monday...Strong high pressure centered across Quebec Province Thu morning will ridge south across the eastern Carolinas. The ridge will drift offshore during the day Thu and Thu night. Strong low pressure across the Midwest Thu night will move to the northeast and gradually weaken. Its attendant cold front will move across the area Fri night. Deep moisture will be tapped ahead of this system, but the best upper level support will pass by to our N. Still expect a likelihood of showers and thunderstorms Fri and Fri night. Drier air will gradually build into the area on Sat as high pressure slowly builds from the NW, but with cool air aloft, can not rule out an isolated shower or thunderstorm. Upper ridge late in weekend will move offshore during Mon and this will allow a very potent southern stream system to bring a heightened risk of showers and thunderstorms across the eastern Carolinas as it lifts NE from the Gulf Coast states into the southern Great Lakes region and brings a surge of deep Gulf of Mexico moisture northward. High temps will be above normal through the period, lower to mid 70s. Lows will be mainly in the 50s. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... As of 00Z...VFR conditions for the evening and much of the overnight. The evening`s convection has pretty much dissipated. However, dynamics aloft toward daybreak Tue become conducive for possible MVFR conditions from either plain shra or an isolated tstorm. The better chance for MVFR and isolated IFR conditions from convection due to better instability and forcing mechanisms occurs between 13Z Tue thru 21z Tue. The cold front will lag behind the convection and will likely push thru late Tue night or early Wed. With plenty of clouds at different levels, radiational type fog tonight should not be widespread if it`s even able to develop. Generally looking at SSW to SW winds 5 kt or less overnight and picking back up to SW 10-15 kt during daylight Tue. Could see a weak resultant wind bndry that backs winds to the S 10-15 kt across the coastal terminals during Tue aftn. Extended outlook...MVFR and possibly IFR Conditions due to widely scattered Tue evening showers/thunderstorms. MVFR and possibly IFR conditions possible from fog Wed morning. MVFR/IFR conditions due to scattered showers and thunderstorms Fri/Fri night. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 815 PM Monday...Looking at SSE to SSW winds around 10 kt for the overnight period. Ridging from the offshore high will drop south of the area...allowing winds to become more SW during Tue. The sfc pg will tighten-some during Tue with wind speeds increasing to 10 to 15 kt. Significant seas will generally run 3 to 4 ft tonight and 3 to 5 ft during Tue. A well established SE ground swell at 10 to 11 second periods will dominate the seas spectrum tonight thru Tue. Even with an increase of wind driven waves during Tue, the SE ground swell will remain the dominant input to the significant seas. Both WaveWatch3 and local SWAN highlight this ground swell. The swell is coming from a rather deep low pressure system well offshore from the SE U.S. Coast that is moving northeast, further away from the U.S. mainland. Boaters navigating to and from area inlets on Tue could encounter rough wave conditions especially during an outgoing tide combined with the incoming 10+ second period swell. SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 3 PM Monday...Expect changeable winds through the period as initially a southwest flow of around 15 knots will be in place. A cold front will quickly move across the waters by 12z Wednesday with a weak west to northwest flow. This modest flow will be in place for about six hours or so before a surge from the northeast commences. This surge will last through the remainder of the period with winds from the northeast on the lower end of a 15-20 knot range. Significant seas will be 3-5 feet early and late in the period with 2-4 feet in between. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 AM Monday...A Small Craft Advisory may be required for all waters Fri and Fri night. Strong high pressure centered across Quebec Province Thu morning will ridge south across the waters. The ridge will drift offshore during the day Thu and Thu night. Strong low pressure across the Midwest Thu night will move to the northeast and gradually weaken. Its attendant cold front will move across the waters Fri night. High pressure will gradually build across the waters from the NW during Sat. The wind direction will be from the NE Thu morning, veering to the E Thu afternoon and SE Thu night. S winds Fri will veer to SW Fri night and then shift to W toward Sat morning. Wind speeds will be 15 to 20 kt Thu and Thu night and may increase to 20 to 25 kt Fri/Fri night. Wind speeds on Sat will be 10 to 15 kt. Seas will be 3 to 5 ft Thu and Thu night, building to 4 to 7 ft Fri/Fri night before subsiding to 3 to 4 ft Sat afternoon. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...DCH SHORT TERM...SHK LONG TERM...RJD AVIATION...DCH
Area Forecast Discussion
National Weather Service Indianapolis IN
1030 PM EDT Mon Mar 27 2017 .UPDATE... The Aviation Section has been updated below. && .SYNOPSIS... Issued at 327 PM EDT Mon Mar 27 2017 An active forecast period is expected for Central Indiana as several troughs and ridges rotate through the area. The first system is currently approaching the forecast area and is expected to produce showers and thunderstorms this evening and tonight. After that, weak ridging will result in dry conditions for mid- week, but another system will approach from the southwest on Wednesday night. This will keep high rain chances in the forecast through the end of the week along with the threat for additional thunderstorms. At that point, the pattern will almost repeat again with a dry period for the weekend followed by another system late in the extended period. && .NEAR TERM /Rest of tonight/... Issued at 1001 PM EDT Mon Mar 27 2017 Radar mosaic shows an area of showers across much of central Indiana at 10 pm. Currently no lightning showing up across the area. However HRRR and RAP continue to show some elevated instability available over the next few hours across the southern half or so of the area, so kept a slight chance for thunderstorms going for that part of the area until 6z. Rain will continue over much of the area until moving out from west to east starting around 6z during the overnight, with dry conditions expected everywhere around daybreak. Cloudy skies will be the rule with low center moving through the area and being in the wake of the low after it moves east. Could see a decent gradient in low temperatures as the northwest could drop into the mid 40s before daybreak as the low moves east (currently a couple obs of mid 40s in northeast Illinois and northwest Indiana), but most of the area should stay in the low to mid 50s. && .SHORT TERM /Tomorrow through Thursday/... Issued at 327 PM EDT Mon Mar 27 2017 Rain showers will end from west to east very early tomorrow morning, and then dry conditions will prevail through Wednesday evening as ridging strengthens aloft. Focus then turns to the next system, which will start impacting Central Indiana on Wednesday night. This system will take almost the same exact path as the near term system, approaching from the southwest. Inserted mention of thunderstorms with this forecast issuance starting Wednesday night across the southwestern counties, spreading northeast across the forecast area on Thursday. As of now, any severe threat with this system is expected to stay south, but this could change quickly with any shifts in the path. Temperatures through the period will be in the 60s, increasing to the low 70s by Thursday as warm advection increases with aforementioned system. Meanwhile, overnight lows will generally be in the 40s with some 50s across the southern counties. && .LONG TERM /Thursday night through Monday/... Issued at 220 PM EDT Mon Mar 27 2017 Timing of showers will be the main focus for the long term. The general weather pattern will remain the same through the long term with alternating Pacific upper lows and ridges. Each upper low will dive southeast across dessert southwest and southern Plains and then lift northeast over the Ohio Valley. Thursday night will start off with the first upper low over the Ozarks. It will open up and move east over the Ohio Valley on Friday. Southerly flow along and ahead of the associated frontal system will bring deep moisture and some instability to the area as well as synoptic forcing. Thus, expect widespread showers and a few thunderstorms from Thursday night through Friday. An upper ridge will follow and should keep the weather quiet from early Saturday through Sunday morning. Then, the next in the upper train will bring shower chances back to central Indiana by Monday. Low level thermal progs and expected cloud cover support slightly above normal blend temperatures with highs in the mid 50s to mid 60s. && .AVIATION /Discussion for the 28/0300Z TAF Issuance/... Issued at 1030 PM EDT Mon Mar 27 2017 With the update...went more pessimistic at KLAF with low MVFR/high IFR developing already and upstream sites showing several obs with IFR ceilings. For KIND added some light showers for the next couple of hours but not convinced these will impact category until after 4z or so. Rest of TAFs on track. Previous discussion follows... Scattered rain showers will bring MVFR conditions over the next few hours for TAF sites across Central Indiana. These scattered showers will move out of the area by midnight leaving behind ceilings that will lower into IFR by sunrise. Some isolated fog will be possible, but with low confidence it will be left out at this time. Ceilings will begin to rise by mid to late afternoon to MVFR and will remain there through the evening. Winds will remain less than 10 knots and generally be north to northeasterly through the period. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...CP SHORT TERM...TDUD LONG TERM....MK AVIATION...White/CP
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1159 PM EDT Mon Mar 27 2017 .UPDATE... Issued at 1159 PM EDT MON MAR 27 2017 Have eliminated the thunder in the far east as the leading edge has moved into West Virginia and Virginia. Also freshened up the POP trends as the southern cold pool showers gradually move east and dissipate. Updates have been sent. UPDATE Issued at 1112 PM EDT MON MAR 27 2017 The severe threat is over, as the last of the storms will exit far eastern Kentucky before midnight, with just some cold pool showers following on its heels, as well as another area of showers affecting locations along and south of the Hal Rogers Parkway and Highway 80 corridors. These showers will exit southeastern Kentucky in the next few hours. There will be lull in the activity following this, until the surface cold front and short wave trough axis nears before dawn. Have allowed for an uptick in showers once again that will carry into Tuesday, before finally diminishing by Tuesday night. Patchy fog will also be seen overnight, especially in areas that saw locally heavy rainfall. Temperatures will not move much from current readings in the mid to upper 50s. UPDATE Issued at 843 PM EDT MON MAR 27 2017 Ongoing complex of strong to severe thunderstorms is gradually winding down as it heads east well ahead of the parent forcing. There are still pockets of severe wind gusts following a persistent lead supercell in the central portion of the forecast area. Expect a continuing gradual decline of this activity through 10 pm, with a lull in the action until a short wave trough axis approaches from the west overnight. This will likely bring an uptick in convection once again, but mainly just showers. Freshened up the POP timing based on the radar trends. && .SHORT TERM...(This evening through Tuesday night) Issued at 440 PM EDT MON MAR 27 2017 A shortwave trough is expected to dampen as it moves into the OH and TN Valley regions through tonight and then across the Appalachians on Tuesday morning and then the Eastern Seaboard by the end of the period. At the same time, a surface low will track near or north of the OH River through this evening and tonight and then into the mid Atlantic states through the end of the period. Height rises and mid and upper level ridging area expected behind the shortwave with surface high pressure nosing into the OH Valley on Tuesday night. Isolated to at times scattered convection continues to move across parts of central and eastern KY in advance of more organized convection over western and west central Ky and western and middle TN. This earlier convection has produced some hail across the region and marginally severe hail and some wind would appear to be a threat over the next couple of hours. MLCAPE of 500 to 1000 J/KG over the far south and MUCAPE of 500 to 1000 J/KG across the area combined with 35 to 40KT of 0-6km shear would support this although much of the area has been worked over and the southwest part of the area should be the first to destabilize again per RAP and model forecasts though much of the western part of the CWA is expected to reach ML or MUCAPE near 1000 J/KG for a time in the west. Satellite trends would also support another window for heating in the south. The far southwest counties remain in a Severe Thunderstorm Watch through 3Z. Trends will continue to be monitored for Severe thunderstorm chances further east, but much of this area has received convection this evening or in the case of the VA border counties has lower sfc dewpoints due to downsloping effects. Some of the convective allowing models bring the convection into east KY around 23Z to 01Z but weaken the eastern line segment as this will near sunset and boundary layer should begin to stabilize. The models generally take the westernmost line east or southeast with the recent HRRR runs favoring southeast while some previous runs brought some of that convection more toward Lake Cumberland. However, pending strength of cold pool, the first more northern line segment of convection may not weaken as quickly as models project as it moves in. Wind appears to be the primary threat with any of this convection with bowing line segments and possibly marginal hail from the strongest updrafts. Locally heavy rain will also be possible if storms could train in an area. Chances for thunderstorms will begin to diminish overnight with shower chances also decreasing late as well as the surface low tracks into the mid OH Valley and the cold front works into the area and the axis of the 500 mb trough approaches. Chances for convection will decrease through the day on Tuesday as the trough and low pressure system exit to the east and northeast and mid and upper level as well as sfc high pressure begin to build in. Low level moisture is expected to linger well into Tuesday night, but if the low clouds thin, radiational fog will be possible and subsidence could bring some stratus build down late Tuesday night. .LONG TERM...(Wednesday through Monday) Issued at 310 PM EDT MON MAR 27 2017 The extended period should once again feature good chances for showers and thunderstorms from late Thursday morning through early Friday evening. The trigger for this activity will likely be a slow moving area of low pressure that is progged to move across the Tennessee and lower Ohio Valley regions. The slow forward motion of the system should keep rain in eastern Kentucky through Saturday morning. Thunderstorm chances should come to an end around 0Z Saturday, as the best upper level support and overall lift should be east of the area as the low pressure system moves off to our east. The rain should begin quickly tapering off around dawn Saturday morning, with the rain being completely out of the area before noon on Saturday. The weather should remain dry from Saturday afternoon through late Sunday night, as an area of high pressure settles over the region. Our next round of rain could move into eastern Kentucky very early Monday morning, but due a lot of uncertainty still exists that far out in the period. Temperatures will continue to run well above normal, with daily highs ranging from the mid to around 70 on most days. Thursday looks to be by far the warmest day, with forecast highs on that day in the 70s. Nightly lows should generally be in the 40s and 50s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 843 PM EDT MON MAR 27 2017 Showers and thunderstorms will exit east across the area through 03z. The stronger cells will contain IFR or worse visibilities with wind gusts of 35 to 40 kts. Ceilings will gradually lower through the night down to IFR levels, as winds shift from the southwest to west northwest behind a passing cold front. Scattered to numerous showers will also continue through dawn, before diminishing from west to east through the day on Tuesday. Ceilings will gradually improve towards the end of the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...JP LONG TERM...AR AVIATION...GEOGERIAN
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
653 PM CDT Mon Mar 27 2017 .SHORT TERM...(This evening through Tuesday) Issued at 335 PM CDT Mon Mar 27 2017 The SREF...HRRR...HRRREXP and RAP models suggest one more round of fog developing late tonight and affecting areas along and east of highway 83 across ncntl Neb. This one looks more like an advection upslope fog event but the models suggest visibility could fall to 1/4 mile. Areas of fog are in the forecast. The rain event for Tuesday continues on track. There have been only minor changes to the forecast...mainly regarding timing. The model consensus is a bit slower with the onset of the rain moving in after midnight tonight. The RAP model indicates precipitable water will increase to around 0.75 inches which is above 200 percent of normal and a very modest 30kt low level jet develops tonight aiming the moisture up the high plains. The moisture advection should continue Tuesday until severe weather gets underway across the Srn Plains. Thereafter easterly upslope winds will draw moisture into the storm affecting wrn and ncntl Neb. The forecast uses a blended approach for rainfall. The SREF and GEF were the wettest solns. These models were able to focus more moisture advection farther north. Temperatures...winds and dew points are a blend of guidance plus bias correction for lows in the 30s and 40s tonight and highs in the 40s and 50s Tuesday which was very close to a blend deterministic model data with or without bias correction. .LONG TERM...(Tuesday night through Monday) Issued at 335 PM CDT Mon Mar 27 2017 An active pattern this week across much of the country, as a series of Pacific storm systems track east and amplify, creating widespread rain in the plains and mountain snow. Some snow may mix in across the western high plains, but accumulations seem unlikely at this time due to mild temperatures. The first system will slowly cross the area Tuesday into Wednesday. A shortwave trough will dig southeast from the Pacific northwest, and be located across northern New Mexico by early Tuesday evening where it will have closed off. Deep southerly mid and upper level flow from TX to NE ahead of the system, with bands of rain moving northward within the flow Tuesday night. By Wednesday evening the system will have migrated to western Oklahoma or southern Kansas, with a deformation band of rain located to it`s northwest. It continues to appear that our far southeast portions from Broken Bow to North Platte stand the best shot of getting in on this deformation band of precipitation, but a slight northward shift of the system would mean more of the area seeing precipitation from the band. By Thursday this will all begin to shift east of the area with some sunshine by afternoon in area of subsidence aloft behind the system. Right now thinking a widespread 0.50 to 1.25 inches of rain will accumulate from this first system, with the 1.25 inch amounts most likely across southwest Nebraska. A second system takes a similar path and dives southeast into northern New Mexico by Saturday. It too is forecasted to close off and then track eastward across the central and southern plains through the weekend. Chance to likely pops will remain in the forecast for this system, with the best chances at this time appearing to reside across southwest Nebraska. As far as temperatures this week, mild conditions with near normal highs in the 50s. Low temperatures, however, will average a bit above normal in the 30s to near 40 degrees due to abundant cloud cover and expected precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 650 PM CDT Mon Mar 27 2017 Clouds will increase from the west tonight with stratus developing generally after midnight. Ceilings will lower into IFR categories with MVFR visibilities as light rain developw over western Nebraska through the early morning hours and slowly moves east. Widespread light rain will continue over most of western Nebraska through the day on Tuesday. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...Taylor AVIATION...Power
Area Forecast Discussion
National Weather Service Louisville KY
716 PM EDT Mon Mar 27 2017 ...Updated Aviation Discussion... .Forecast Update... Issued at 620 PM EDT Mon Mar 27 2017 Still have some pre squall line storms popping up with hail and some winds. Just had a report come in from Nelson county of quarter sized hail. Other line is just along our border with JKL. Main line has cut through roughly half of the forecast area, so went ahead and cut out part of the watch box behind the line. Watching the bowing segment over southern Indiana as well, but the FRH AWOS site only gusted to 27 knots as the line went through. Issued at 520 PM EDT Mon Mar 27 2017 Latest RAP mesoanalysis has not been handling the amount of available CAPE well, as we`ve had several hail reports, mostly quarter sized or less, though cannot rule out some larger hail in the pre-frontal airmass from FTK east to KLEX over the next few hours. The other area of concern is with the more linear feature moving near the I-65 corridor in Central KY this hour. This area has the most potential instability to work with, as temperatures are well into the 70s along our border with TN. Seeing some bowing segments within this line and have issue warnings accordingly. HPX radar was showing winds closer to 70 mph with this line, but have not had any reports near that level just yet. && .Short Term...(This evening through Tuesday night) Issued at 330 PM EDT Mon Mar 27 2017 ...Severe Storms Possible Late This Afternoon and Evening... Strong to severe storms are likely this afternoon with much of the area under a Severe Thunderstorm Watch through this evening. These storms are courtesy of a low pressure system moving northeast through southern IN/northern KY. 1000-2000 j/kg of CAPE has developed south of the warm front which was over southern IN as of 315pm EDT. 30-40 kts deep layer shear is supportive of both discrete cells which we`re seeing on radar in our region currently and will be supportive of the line of storms over western KY which is progged to move east through the region between 5pm-midnight tonight. ======================== Storm Threats & Timing ======================== Cellular convection will pose a large hail/damaging wind/isld tornado threat between now and 8pm EDT. Expect mainly a damaging wind threat with the line of storms but small hail and a brief spin-up will be possible as well between 5pm and midnight EDT. ========================= Convection should decrease after midnight with elevated showers and perhaps an isld t-storm during the early morning hours in the wake of the evening complex. Overnight lows will range through the 50s. For Tuesday, expect some lingering rain showers mainly east of I-65 before the area becomes totally dry late in the day. High temperatures will be in the 60s. Lows Tues night will range through the upper 40s/lower 50s. .Long Term...(Wednesday through Monday) Issued at 345 PM EDT Sun Mar 26 2017 Expect dry weather on Wednesday before the pattern turns active again for the latter portion of the week. A strong low pressure system will bring the chance for showers/storms to the region beginning on Thu/Fri. Depending on exact evolution and timing, some of these storms could be on the strong side. Thu looks to the be the warmest day in the long term period with highs in the mid to upper 70s across much of the area. For the weekend, expect dry weather and slightly cooler temps with highs dropping back into the 60s. Another low pressure system looks to approach the area again by the beginning of the work week next week. && .Aviation...(00Z TAF Issuance) Issued at 715 PM EDT Mon Mar 27 2017 Line of storms now getting into LEX, with residual rains, occasional lightning, at the other sites. Will see the worst of it end in the next few hours, then get a break by just after midnight before some lower ceilings kick in. Have gone low-end MVFR at BWG/SDF around daybreak, but went worse for LEX through the morning hours, based on time height sections and longer time in the moisture overnight in the east. Lower ceilings should stick around for much of the day Tuesday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RJS Short Term...AMS Long Term...AMS Aviation...RJS
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
958 PM CDT Mon Mar 27 2017 .DISCUSSION...See updated information for land and marine areas below. && .UPDATE...Upstream deep convection on the wane as forecast. Will have to watch because there are still some marginal strength updrafts updraft for SPS/sub-severe criteria. Those updrafts will continue moving very slowly east in the flow until they weaken altogether in the next few hours. MLCAPES down 200-600 J/KG from 3 hours ago. Did have one multicell with a large weak echo region / very reflective elevated mid-level reflectivity core that moved across Wayne Co., MS and into Choctaw/Washington Co., AL border region. Getting some verification from that where we suspect hail diameters from between 1-1.5" diameter. We appreciate the reports received thus far. Did a quick update to the grids and text products to better describe the fog evolution overnight. Also left a slight rain chance to the north through midnight. Finally, removed headline for high rip current risk (see earlier discussion). && .MARINE...42012 is back on-line (now with dewpoint). Significant wave heights across the marine area generally anywhere from 2-3 feet with wave periods 5-6 sec. No changes to marine package overnight. && .PREV DISCUSSION... /issued 628 PM CDT Mon Mar 27 2017/ DISCUSSION...See updated information below. UPDATE...Main impact to our area next few hours will be broken line of multicells-supercells now moving into NW corner of our area (Choctaw Co., AL). These updrafts will be capable of supporting severe hail (1-1.5" in diameter) and possibly damaging straight line winds. Developing updrafts further SW, to affect our interior SE MS counties within the hour. As thought all along, Choctaw- Wayne, Clarke and Wilcox stand the greatest chances of experience an isolated severe thunderstorm through mid- evening. The line will proceed east early this evening and main impact will be large hail and possible damaging straight line winds. MLCAPEs in ambient environment ahead of line range from 750 J/KG NW zones to near 1500 J/KG closer to the coast. Instability trend is down past few hours, of course given time of day. Nearly 35-40 kt of bulk shear supporting both multicells (with observed new cell growth on low-level SW flank) and occasional supercells (observed deep persistent rotation where propagation forces storm motion to right, temporarily). Latest guidance shows these storms will be affecting our region with waning intensity through 9-10 PM and that should just about do it. Will allow High Risk of rip currents to finally go to `Moderate` around dark, thus RP.S will expire. Did make some tweaks to grids to reduce rainfall amount for interior sections tomorrow afternoon. /23 JMM AVIATION... 00Z issuance...Pretty much a forecast of persistence overall, as with last night. With sunset, will see mainly stratus rolling inland again by 03Z from S to N with mainly CIGs falling into IFR-LIFR range through midnight. Condition persists with occasional sfc vsbys at some TAF sites dropping below 1 SM from 6-10 UTC. After sunrise, VFR conditions by 15 UTC regionwide. Tomorrow afternoon, cloud streets will keep some occasional broken MVFR CIGs around int he afternoon. Light S winds with low end gusts subsiding by 02 UTC and resuming after 16 UTC tomorrow, especially near the coast. /23 JMM PREV DISCUSSION... /issued 413 PM CDT Mon Mar 27 2017/ NEAR TERM /Now Through Tuesday/...Thunderstorms developing over central MS to northern and central LA within an airmass characterized by increased afternoon instability (MUCAPES having increased to 2000-3000 J/KG). Latest high resolution HRRR is more robust on carrying activity eastward, showing a series of organized convective clusters passing over the interior zones this evening. A few of the storms could produce marginally severe hail and localized damaging wind gusts. The other guidance, NSSL WRF- ARW and the 3 KM NAM are not as pronounced with their respective solutions. Late afternoon and evening updates to storm coverage over the interior will likely be required depending on convective trends upstream. Upper level storm system/trof axis over the Mid-South to begin the near term, makes steady eastward progression across the Appalachians Tuesday morning. A narrow zone of deep layer moisture (pwats around 1.25") hangs back across the interior tonight and provides enough moisture to maintain a small chance of showers/storms over the northwest zones late. Surface pattern remains mostly unchanged. A ridge of surface high pressure off the Mid-Atlantic, ridging southwest into the central Gulf maintains a persistent, light southerly flow and dewpoints well into the 60s. This synoptic pattern favors the development of overnight fog which could become dense in some areas. Overnight lows in the lower to mid 60s. Despite, short wave mid-level ridge moving eastward across the forecast area Tuesday, east to west zone of deep layer moisture holds which supports the potential of showers and storms during daytime heating when instability is better. Though, with the presence of the upper ridge and its associated sinking vertical motions to act as a counter to convective development, will only keep probability of showers and storms in slight chance ranges Tuesday. Tuesday`s highs in the lower to mid 80s interior and mid to upper 70s beaches. /10 SHORT TERM /Tuesday night Through Thursday night/...A significant weather event is forecast for Thursday and Thursday night as a strong storm system approaching the region from the west moves across the area. A 100-120 knot 300 mb jet max over the far western conus will carve out a highly amplified upper level trough over the southern Rockies and northern Mexico by Tuesday evening, with an embedded closed low forming over the desert southwest. This upper trough and low pressure area will then advance eastward over the southern Great Plains midweek. The closed low is forecast to be over eastern Oklahoma Thursday morning, take a turn to the northeast, reaching extreme southern Illinois by late Thursday night. Meanwhile the southern portion of the trough is expected to swing quicker to the east, aided by a 90 knot jet streak, and possibly become slightly negatively tilted over the region late Thursday night. A surface low pressure area is forecast to develop near the north Texas/southwest Oklahoma border Tuesday night ahead of the advancing upper level trough, and move east over eastern Oklahoma by Thursday morning. This surface low will also take a turn to the northeast, also reaching extreme southern Illinois by late Thursday night. An associated cold front approaching the region from the west Thursday evening will sweep through the forecast area after midnight. A deep southerly wind flow ahead of the system will advect moisture northward across the region, with precipitable water values climbing to between 1.5 to 1.7 inches Thursday afternoon and evening. Both the ECMWF and GFS models are advertising MLCAPE values between 500 to 700 J/KG on Thursday, with SFC-1km storm relative helicity values ranging from 100 to 200 m2/s2. A 30 to 40 knot low level jet is also expected to accompany this system. Upper level lapse rates will be in the 7 to 7.5 c/km range. The pre-storm environment will favor the development of strong to severe thunderstorms throughout the day Thursday into Thursday night as a line of numerous storms advances east through the region. Damaging winds, large hail, and isolated tornadoes are all possible with this system. Heavy rainfall will also occur with widespread 1 to 2 inches likely. Otherwise it will be dry Tuesday night through midweek as an upper level ridge moves east over region, along with a surface high pressure ridge across the southeastern states and eastern gulf remain largely intact. Low temperatures each night will range from 58 to 62 degrees inland areas, with mid 60s along the beaches. Warm temperatures will continue on Tuesday and Wednesday with highs ranging from 80 to 85 degrees inland areas, with mid to upper 70s along the coastal sections. /22 Low temperatures each night will range from 58 to 63 degrees inland areas, with mid 60s along the beaches. Warm temperatures will continue Wednesday with highs ranging from 81 to 86 degrees inland areas, and from 75 to 80 degrees along the coast. /22 LONG TERM /Friday Through Monday/...The precipitation will then taper off from west to east late Thursday night and early Friday in the wake of the cold front, followed by high pressure building in from the west. The dry period will then persist through the remainder of the week as an upper ridge and surface high pressure dominate the southeast states. Precipitation chances will increase once again early next week as yet another upper level trough develops to our west and advances east over the southern plains, with scattered showers and thunderstorms forecast for Sunday afternoon through Sunday night. Above normal temperatures will continue through the long term. /22 MARINE...High pressure to the east maintains a light onshore component of flow through the middle of the week with seas 2 to 4 feet in range. A stronger onshore flow and resultant fetch brings higher seas Thursday ahead of a frontal boundary approaching from the west. Increased coverage of showers and storms are expected as this weather system approaches, with a few strong to severe storms possible late Thursday. Winds decrease and seas show a slow subsiding trend going into the upcoming weekend. /10 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at: http://weather.gov/mob
Area Forecast Discussion
National Weather Service Paducah KY
624 PM CDT Mon Mar 27 2017 .UPDATE... Issued at 618 PM CDT Mon Mar 27 2017 Updated for 00z aviation only. && .SHORT TERM...(Tonight through Wednesday night) Issued at 138 PM CDT Mon Mar 27 2017 Near term convective (svr) environment continues, with best threat area appearing now to be shifting to Lakes/eastward across southern Pennyrile, where best dew point surge/area of some breaks/highest MU Capes coexist. Area of ongoing convection has picked up steam, from around 32Kts earlier today to ongoing around 40Kts now, and this is anticipated as upper jet is moving in. This should propel convection thru southern Ky fairly quickly, with HRRR modeling the ongoing activity reasonably well, and taking bulk of its pcpn thru the area/into scntl Ky/cntl Tn by 23Z. Will go near certainty Pops til then, and cut into them drastically afterwards. May maintain upper trof/instability shower chance or slight chance, esp east, overnight however. After tonight, Tuesday offers a pause, with the upper ridge nudging across the mid Mississippi/Tennessee valleys. Then another robust storm system takes shape and ejects across the southern Plains, moving its convection into the lower and mid Mississippi valleys Wed night-Thursday, with maybe some warm sector/advection chances showing up earlier, esp west, during the day Wed. A similar environment is encountered so we are outlooked SWODY3 Marginal to Slight risk for late Wed night into Thursday morning, with the 15% bubbling across western Ky Thursday, not too dissimilar to today. .LONG TERM...(Thursday through Sunday) Issued at 329 PM CDT Mon Mar 27 2017 A very active split flow pattern will continue across the CONUS later in the week. The ECMWF has been less consistent than the GFS with keeping the flatter northern and the amplified southern stream unphased (phasing tended to result in faster forward movement). However, the 12Z runs of the deterministic models seemed to be back in reasonable agreement, and the consensus is that the PAH forecast area will be affected by two systems in the extended forecast, one on Thu/Fri which should hold together and move across our region, and another probably on Mon which may become an open wave as it approaches. Overall, PoPs should remain rather high Thu/Thu night with the first large low pressure system, though there may be at least one interval of dry slotting in the warm sector sometime during the day Thu. Thunderstorm chances should diminish from west to east Thu night, but there might be a resurgence of instability during the day Fri for the eastern half of the region under the mid level low. At this time, the weekend looks mostly dry under mid level ridging and a ridge axis of high surface pressure. As early as Sun night, showers associated with the next low pressure system may occur in the west, and expand across the region Mon. However, at Day 7, there were significant model differences regarding the timing and positioning of the system, so the forecast is subject to change. Expect unseasonably warm temps Thu, followed by a drop of around ten degrees on Fri, and a slow rebound through the rest of the extended period. && .AVIATION... Issued at 618 PM CDT Mon Mar 27 2017 After a brief break in the cloud cover expect MVFR cigs to return overnight and likely stick around for most of the valid time of this issuance. Cant rule out isld shower as the low pulls out and winds slowly shift to the north all locations between 3 and 6z tonight. As the low deck builds and winds decrease there will be some MVFR fog overnight until after sunrise Tuesday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ AVIATION...KH
Area Forecast Discussion
National Weather Service Blacksburg VA
949 PM EDT Mon Mar 27 2017 .SYNOPSIS... Moist southerly flow will continue tonight into Tuesday, with several rounds of showers and thunderstorms possible. Low pressure in the Ohio Valley with a trailing cold front will lift east tonight into Tuesday. Behind the front, drier air will arrive for midweek. && .NEAR TERM /THROUGH TUESDAY/... As of 940 PM EDT Monday... Changes to the forecast this evening amount to mainly very short term adjustment to chances of additional showers and and storm through the next few hours. Adjustments will be based upon the latest radar trends, which place isolated to scattered coverage across the far southeast portion of the forecast area, and soon-to-be arriving scattered showers and a few storms across the far western portions of the area. As the night progresses, the forecast will reflect progressively increasing chances of showers from west to east as a cold front approaches the area through the Ohio and Tennessee Valleys. As of 350 PM EDT Monday... Isolated to scattered convection developing ahead of the cold front this afternoon in the warm and unstable air. This convection is developing ahead of a lead shortwave moving ahead of an upper trough. The convective outlook for Day 1 places the marginal risk of severe weather to our west with the best instability and dynamics. Highres models like the HRRR and ARW showed isolated convection developing this afternoon into tonight, especially along the southern Blue ridge. Models enhance lift and low level convergence across the Blue Ridge into the foothills after midnight into the overnight as the front approach the Appalachians. Low temperatures tonight will range from the upper 40s in the mountains to near 60 degrees in the Piedmont. A strong cold front will move across our region Tuesday into Tuesday night. Scattered showers and Thunderstorms will develop ahead and along this boundary. The SWODY2 has placed eastern portions of CWA in a marginal risk for Tuesday. The timing of the shortwave on Tuesday with a favorable area of forcing for ascent moving across eastern portions during the afternoon during peak heating. The shortwave should move offshore around 29/00Z. The strongest storms could produce hail and locally damaging wind gusts. High temperatures Tuesday will vary from the upper 50s in the mountains to the mid 70s in the Piedmont. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 349 PM EDT Monday... A cold front will move across the region Tuesday night with showers exiting the piedmont during the evening. Some low level moisture may squeeze out a few showers along western slopes overnight as the theta-E boundary tracks south across the mountains. There is not much cold air air behind this front, so any precipitation along western slopes or across the mountains will be liquid and not frozen. High pressure will move south out of Canada Wednesday, then wedge down the east coast Wednesday night into Thursday. This wedge will initial be dry and mostly clear Wednesday. Wednesday afternoon temperatures will warm into the 60s west to 70s east. A strong area of low pressure will track out of the Rockies Wednesday then across the Midwest Thursday night. This system will throw warm moist air over the wedge, increasing clouds and eventually the chance for rain/drizzle. Saturation of the environment should not occur until late Wednesday night into Thursday morning. Isentropic lift increases during the day Thursday. With this in mind, we have delayed the onset of stratiform rain/drizzle until late Thursday morning and moreso along eastern slopes of the North Carolina High Country and Grayson Highlands. The combination of rain falling into a linger wedge will produce cool temperatures with highs in the 50s areawide Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 349 PM EDT Monday... A strong area on low pressure will track from the Midwest to the south-central Appalachian mountains Thursday night into Friday. This low will erode the wedge of cooler air that moved into the region Wednesday. Dynamics from this low and with a retreating wedge boundary, there is the possibility strong storms could develop across the region Friday into Friday evening. However, timing is everything with this event. Currently, models have dynamics and retreating wedge environment occuring during the morning, which lowers the threat for severe weather. If this event occurs later in the day, then the threat for severe weather will increase. With an eroding wedge, temperatures will increase Thursday night and into the day Friday. Lows Thursday night will occur around midnight (upper 40s), then rise into the low to mid 60s Friday afternoon. This low pressure system and associated showers will exit the mid Atlantic coast Friday night. Dry high pressure and near normal temperatures will follow for the weekend. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... As of 805 PM EDT Monday... Widespread mid and high VFR clouds will cover the Mid Atlantic region tonight and Tuesday ahead of an upper low that will cross through the Ohio Valley. Isolated to scattered showers and thunderstorms with MVFR ceilings and visibilities are expected through 06Z/2AM. A cold front will extend from a low in Ohio across the Tennessee Valley by 12Z. Numerous showers and scattered thunderstorms with MVFR ceilings and visibilities are expected late tonight and through Tuesday along and ahead of the front. MVFR to IFR ceilings will develop late tonight along the Appalachians. Low confidence with how extensive the lower clouds will be. Winds will be from the south to southeast ahead of the front and from the west behind the front. Extended Aviation Discussion... The cold front exits the Virginia and North Carolina piedmont after 00z Wednesday with lingering sub-VFR cigs in BLF/LWB with VFR in the east of the Blue Ridge. High pressure builds in from the north Wednesday into Thursday with next storm system moving in the Mississippi Valley. A threat for sub-VFR cigs appears likely as the high wedges southwest Wed night into Thursday for most sites. The highest probability of rain will be on Friday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...DS/KK SHORT TERM...RCS LONG TERM...RCS AVIATION...AMS
Area Forecast Discussion
National Weather Service San Diego CA
200 PM PDT Mon Mar 27 2017 .SYNOPSIS... Low pressure aloft will bring gusty west winds to the mountains and deserts through early this evening. Otherwise, partly cloudy skies will prevail west of the mountains with temperatures a little below normal. High pressure building into the Great Basin will bring locally gusty northeast winds below passes and canyons tonight and Tuesday. Mostly clear skies will prevail Tuesday and Wednesday with warmer weather. Another low pressure system will move by to the northeast Thursday and Friday and will bring strong westerly winds to the mountains and deserts and cooler weather. Fair and warmer weather will prevail next weekend under high pressure, with another low pressure system possibly bringing cooling again early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Partly cloudy skies prevailed west of the mountains with a small amount of lingering fog along the coastal mountain slopes. The marine layer was generally 5000-6000 feet deep which resulted in the slow clearing in the valleys and foothills. West winds were strong in the mountains and deserts with a 59 MPH gust at White Water West just east of San Gorgonio Pass at mid-morning, though most windy areas had peak gusts between 40 and 50 MPH today. Local WRF model, HRRR and Cansac-WRF show these winds continuing through around 7 PM tonight, then weakening somewhat as offshore flow develops. The low pressure trough axis was over So-Cal with two main waves but not enough moisture for precipitation in our forecast area. The trough will shift to the Four Corners tonight with rather tight height gradients under NW flow behind the trough. A surface high will build over northern Nevada late tonight and Tuesday and contribute to moderate offshore flow, with surface MSLP gradients around 10 MB from west-central Nevada to San Diego, though very much northerly in orientation versus northeasterly. That will result in winds below E-W ridges, mainly San Bernardino County, with some winds in the Santa Ana Mountains. Mountain waves will not be particularly strong, with most of the winds below the crests but not as much in the valleys, except briefly late Tuesday morning after surface heating results in some mixing. Overall, peak gusts will be 45-60 MPH. San Diego County will see very little of this wind due to the northerly gradients. Winds will mostly decrease by Tuesday mid- afternoon. By Tuesday morning, most areas will be clear, so that combined with the cold low having exited to the east, will result in 5-10 deg F warming in most areas to slightly above normal. Wednesday should be quite warm with temps around 10 deg F above seasonal normals, which means a lot of 80s in the Inland Empire and far inland valleys of San Diego County. Models continue to have a deep low tracking from far northern California to far northern Arizona from Thursday to Friday. This inland track will most likely keep our area dry, but the mountains and deserts could have strong winds, especially late Thursday and Thursday night. Temperatures will decrease, though just to near or very slightly below normal by Friday. The low will track east over the weekend with fair weather to follow. Offshore flow will be rather weak though. Temps will increase again to 5-10 deg F above normal by Sunday. Another inland closed low could drop down from the north early next week. && .AVIATION... 272040Z...SCT-BKN025-035 Tops 5000 ft through 03Z. An intermittent ceiling near 3000 feet is possible at KSAN and KCRQ through 12Z Tuesday. Mostly clear skies Tuesday. Strong westerly winds 20-40 kt over the mountains and into some of the deserts tonight with areas of strong up/downdrafts and LLWS over and east of the mountains. The winds shift northeasterly after 04Z Tuesday, surfacing in the Inland Empire through 23Z impacting KONT, KSBD and possible KSNA with strong up/downdrafts and LLWS. && .MARINE... A Small Craft Advisory is in effect for strong northwest winds and rough seas through Tuesday. Northwest winds will increase again Thursday and continue through Friday leading to more choppy seas and hazardous boating conditions. && .BEACHES... West to northwest swells will bring elevated surf of 3 to 6 feet most of the week with occasional sets to 7 feet. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory until 10 PM PDT this evening for Apple and Lucerne Valleys-San Diego County Deserts-San Diego County Mountains. Wind Advisory from 10 PM this evening to 2 PM PDT Tuesday for San Bernardino and Riverside County Valleys-The Inland Empire-Santa Ana Mountains and Foothills. Wind Advisory until 2 PM PDT Tuesday for Riverside County Mountains-San Bernardino County Mountains-San Gorgonio Pass Near Banning. PZ...Small Craft Advisory until 8 PM PDT Tuesday for Coastal Waters from San Mateo Point to the Mexican Border and out to 30 nm- Waters from San Mateo point to the Mexican Border Extending 30 to 60 nm out including San Clemente Island. && $$ PUBLIC...Maxwell AVIATION/MARINE/BEACHES...Moede
Area Forecast Discussion
National Weather Service Topeka KS
612 PM CDT Mon Mar 27 2017 ...AVIATION UPDATE... .SHORT TERM...(This evening through Tuesday) Issued at 241 PM CDT Mon Mar 27 2017 Shortwave trof that brought rain across the area into early this morning has moved east of the area, and continues to wrap low clouds back southwestward into the forecast area. Starting to see some breaks with the afternoon sunshine, but think this may be short lived. Lingering cloud cover should hold overnight lows in the 40s, with highs on Tuesday rising toward 60 most areas. High pressure moving in from the north keeps northerly winds early, becoming east southeast into Tuesday afternoon. Was hoping for some breaks in the clouds, but as winds veer around from the east this would aid in keeping low clouds lingering across the east. Western counties should see an increase in mid/high clouds by late afternoon, with an outside chance for rain far west in the late afternoon, but think better chances are later in the evening and overnight. .LONG TERM...(Tuesday night through Monday) Issued at 241 PM CDT Mon Mar 27 2017 The weather pattern in the long term looks and cool and wet. The models are in good agreement in the mass fields with two more significant upper lows moving through the southern plains this forecast period. The first should emerge into the southern plains on Tuesday and then slowly move ENE with the 500 mph low reaching SW Missouri by 18Z Thursday per the 12z ECMWF which is expected to be vertically stacked with the surface low in the same location. The 12z GFS is in the same general area with the upper low, but it is northwest over eastern kansas. With respect to the sensible weather in northeast Kansas, all the 12z synoptic models are reasonably close with a prolonged period of cool rain. There is enough elevated instability to justify thunder in the forecast. QPF should be high and there might be local flooding issues if the rain can focus over a given area long enough. The second upper low approaches the southern plains by this weekend. We can expect 36 to maybe 48 hours of dry and cool weather late this week into the weekend before the precipitation associated with the next upper low moves in. There is certainly more model differences with the next system, but there is enough confidence to forecast more rain. Overall, we can expect below normal temperatures through the period in the pattern. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 612 PM CDT Mon Mar 27 2017 The RAP and NAM have tended to keep MVFR CIGS over the terminals as 925MB winds back to the northeast and east. With satellite showing an expansive cloud shift to the northeast, this makes some since. There could be some tempo VFR CIGS this evening, but think MVFR clouds should be predominate most of the forecast period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...Johnson AVIATION...Wolters