Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/13/19

Area Forecast Discussion
National Weather Service Bismarck ND
909 PM CDT Fri Apr 12 2019 .UPDATE... Issued at 909 PM CDT Fri Apr 12 2019 Latest local/regional radar shows the back edge of higher reflectivities supporting scattered snow showers extends from Carrington to Jamestown, and snaking back into Linton. This is on track to weaken and exit the southern James River Valley between 10PM and 11PM CDT. Surface high pressure in southeast Saskatchewan will slowly shift into western South Dakota by 12z Saturday. Clouds will gradually decrease from west to east overnight. Minor adjustments to PoPs and sky cover overnight based on the above discussion. UPDATE Issued at 552 PM CDT Fri Apr 12 2019 Upper low now in eastern Minnesota continues to rotate clouds and scattered snow showers into central ND. Radar reflectivities continue to show a weakening trend with a north to south movement, and PoP trends from previous forecast looks good. Expect the majority of the snow showers over the James River Valley, and less farther west this evening. Still quite a bit of strato-cumulus clouds across western ND, with overcast conditions for most of central ND. Following the HRRR 925mb Relative Humidity fields overnight, expect a gradual clearing west into central, with the southern James River Valley holding onto the clouds until 10-12z Saturday. Per RAP BUFKIT soundings at Jamestown, Ashley and Oakes, prospects of fog where we had heavy snowfall looks low at this point, given the the persistent clouds through most of the night and high enough winds/turbulence within the lower boundary layer to inhibit the threat for fog. && .SHORT TERM...(This evening through Saturday) Issued at 322 PM CDT Fri Apr 12 2019 Water vapor analysis places the closed low centered over Minnesota with western and central North Dakota under a region of increasing upper level confluence. Scattered snow and rain showers wrap around the back side of the associated surface low this afternoon before tapering off from west to east through the evening as a surface high builds from the west. Clearing skies tonight with diminishing winds will drop low temperatures into the low 20s with upper teens possible in some areas. The challenge tonight with lows will be how quickly cloud cover can vacate. If skies clear over areas with fresh snow, temperatures may need to be lowered. While there is an outside chance of fog with the fresh snowpack, the placement of the surface high axis to the west of the snowpack tonight doesn`t give enough confidence to include mention in the forecast. For Saturday, a weak mid-level ridge builds over the state with a surface high centered over central South Dakota. With clear skies high temperatures reach the mid 50s in the west and 40s in the south- central. .LONG TERM...(Saturday night through Friday) Issued at 322 PM CDT Fri Apr 12 2019 Temperatures will warm to near average for next week as zonal flow begins to dominate, with some chances for mixed precipitation throughout the extended forecast. First chance of precip is Sunday night into Monday morning with a weak warm front dragging south of a clipper. The main issue is going to be what kind of mixed precip, with daytime highs in the 40s and 50s and Sunday night`s low right around freezing. Both the 12Z GFS and ECMWF have very light QPF, along with just a chance of PoPs in the grids overall. Therefore, whatever p-type we end up getting, likely won`t be too much of it. Very slight cooldown after the first system before a potentially more significant storm for the Central Plains midweek, with again some possible p-type issues. GFS has the system faster and weaker than ECMWF, resulting in a more spread out precipitation field north of the low, whereas ECMWF has precip ending close to the ND/SD border, leaving us out completely. There`s a wide spread in QPF possibilities from the 0Z GEFS plumes so still plenty of uncertainty this far out. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 552 PM CDT Fri Apr 12 2019 KJMS will continue to experience mvfr cigs and periods of mvfr visibilities in -shsn until 05z Saturday, then gradually returning to vfr by 10z. Elsewhere, low vfr cigs at the remaining terminals to start the 00z taf cycle will undergo a gradual clearing sky overnight into most of Saturday. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...AE LONG TERM...MJ AVIATION...KS
Area Forecast Discussion
National Weather Service Denver/Boulder CO
852 PM MDT Fri Apr 12 2019 .UPDATE... Issued at 852 PM MDT Fri Apr 12 2019 This afternoon and evening`s convection was not as strong as many models had been predicting. Current radar and GOES-16 imagery snowing convective snow showers (even some rain) continuing to move across the area with minimal impacts so far. The current batch of showers is being forced by an approaching trough axis and a strong pool of cold air aloft. Upslope enhancement is not expected to be much of a factor tonight for any particular location across the foothills and Palmer Divide, thus it`s difficult to pin down any favored area for better snow chances. The 00Z KDNR sounding showed very steep lapse rates all the way to the tropopause and it is -26degC at 500 mb. Suffice to say convective snow showers with the trough axis still back over central/eastern Utah will be possible across a good part of our area until about 5 AM or so. Coverage at this point still appears spotty but around a half inch could fall with any shower/batch of showers right overhead. We think at most 1-2 inches in a few spots are possible through sunrise. Temperatures for the next several hours are still warm enough to result in wet pavements, so accumulation should be restricted to the grass until after midnight. Any snow that falls after midnight could result in slick spots on roads, especially for bridges and overpasses given air and road temps gradually falling below freezing after midnight. The forecast overnight is mostly on track. We reduced snow amounts through midnight given what we`ve already seen vs. what the high res models tried to generate, and adjusted PoPs to reflect where the HRRR is trending the convective snow showers after 10 PM or so. && .SHORT TERM...(This evening through Saturday) Issued at 346 PM MDT Fri Apr 12 2019 An upper trough axis stretching along western Colorado state line down onto old Mexico will slowly move east overnight where it will become a cutoff low near southeastern NM and western TX by Saturday morning. Instability in the airmass over Colorado is allowing scattered snow showers to spread across the mountains and urban corridor. Upward QG lift will be increasing this evening as moisture streams up from southern Colorado, while northeasterly winds from a surface high pressure over the northeastern plains should focus shower activity over the higher terrain along and south of I-70 and east over the Palmer Divide. Seems as the hourly high res models keep pushing the brunt of the showers a little later each run. So this may be closer to the later evening, rather than affecting the evening commute. As the night progresses, these showers will move east and north over the front range urban corridor and adjacent plains. 700 mb flow will be southerly, so should start to downslope and dry out further north from the Palmer Divide and into the metro area. 2 to 3 inches are expected over the Palmer Ridge while less than an inch is expected north. The mountains will likely see 1 to 3 inches, except 3 to 6 inches south of I70 and into the southern foothills. Quite a bit of model discrepancy of chances for precipitation past midnight out on the eastern plains. GFS is the heaviest and furthest north and east with snow continuing, so would like to consider it the outlier and not nudge the forecast toward it. However the 18z NAM came in following its solution, have stretched some of the PoP and QPF north into the eastern Colorado counties. The trough axis will pass overhead Saturday, though QG lift will be decreasing. Some showers still expected, still favoring the higher terrain, with a slight chance of thunder being heard late afternoon over the mountains and urban corridor. Only small pea size hail would be expected however. Temperatures will be similar to slightly warmer tomorrow. .LONG TERM...(Saturday night through Friday) Issued at 346 PM MDT Fri Apr 12 2019 Northwesterly flow aloft is expected over the CWA on Saturday night. Flat upper ridging is in place Sunday into Monday. Southwesterly flow aloft is progged the rest of Monday and Monday night. The QG Omega fields have downward vertical velocity for the CWA Saturday night through Sunday evening. Benign energy is place Sunday overnight through Monday evening, with upward upward motion to move Monday overnight. The boundary layer winds will follow normal drainage patterns during the nights, with the weak downsloping flow to dominate both Sunday and Monday. For moisture, there is some lingering around early Saturday evening, then the moisture is pretty sparse in most areas. There will be some moisture in the high mountains Sunday into Monday. There might be a tad of upper level cloudiness in some areas Sunday through Monday night. There is practically no CAPE progged over the CWA Saturday night through Monday night. There are tiny amounts over measurable precipitation on the QPF fields Saturday evening, Sunday afternoon & night, and late day Monday. It is indicated over the far northwestern corner of the CWA those periods. For pops will go with "chances" over the high mountains, especially zone 31 mainly during the late day/evening periods. For temperatures, Sunday`s highs are 5-12 C warmer than Saturday`s highs. Monday`s highs are 3-4 C warmer than Sunday`s. For the later days, Tuesday through Friday, there will be southwesterly flow aloft on Tuesday, with an upper trough to moves over the CWA Tuesday night into Wednesday morning. Northwesterly flow aloft is then in place the rest of the week. There will be decent moisture around Tuesday afternoon through Wednesday night. Moisture will linger, especially in the mountains into Friday morning. There is measurable precipitation noted from Tuesday afternoon through Wednesday evening. There is some to continue, mainly in the mountains, into Friday morning. Tuesday is still above normal for temperatures, then they cool off the rest of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 852 PM MDT Fri Apr 12 2019 Challenging meteorological forecast for the TAF sites tonight and Saturday but overall the impacts are expected to be fairly well handled despite the uncertainty in wind/snow/rain/CIG. First, convective snow showers continue to be possible at all three terminals tonight. Runway temperatures continue to be warm this evening so do not expect any accumulation on runways through about midnight. After midnight, snow accumulation on the runways will be possible as temperatures drop. Current thinking would be up to a half inch accumulation through 3 AM or so. Can`t rule out an inch of snow if more than one shower moves over an airfield. By 3 or 4 AM the threat of accumulating snow should be over. Winds will remain 10 kts or less, generally out of the east or east- southeast. CIGs and VIS have been hard to pin down with these showers, but generally we believe MVFR will prevail, even in the snow showers. There is an isolated chance of brief IFR conditions if any showers are heavier than expected. Saturday morning after sunrise conditions should be MVFR and dry, and improve to VFR by midday. Winds should shift to north around midday and then another round of convective showers after 2 PM are possible at all three terminals. At this point, it looks like precipitation will fall as rain and MVFR conditions expected during any precipitation. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Schlatter SHORT TERM...Kriederman LONG TERM...RJK AVIATION...Schlatter
Area Forecast Discussion
National Weather Service Caribou ME
926 PM EDT Fri Apr 12 2019 .SYNOPSIS... An occluded front will cross the area with showers tonight. Low pressure lifting up to our west will track into Canada late tonight into Saturday. High pressure will build over the area Sunday. Low pressure will approach from the southwest on Monday. && .NEAR TERM /THROUGH SATURDAY/... Update... Latest radar reflectivity imagery shows a broken line of showers stretching from the St. Lawrence seaway southwest into New Hampshire. Have lowered pops early this evening, as showers have been slower to push into the forecast area than previously forecast. Latest HRRR still indicating showers will move into most of the area after midnight, or shortly thereafter. Thus, will hold onto categorical pops after midnight. We did lower six hourly QPF amounts in to 00z to 06z time frame, with the slower onset of showers into the forecast area. Adjusted current temps/ dew points based on latest observations, but no changes to previously forecasted overnight lows. previous discussion Low pressure lifting up to our west will pull an occluded front across the area tonight bringing clouds, a mild breeze and some showers. Around a quarter inch of rain is expected overnight with most of the rain falling from mid evening until around dawn. The front will continue east on Saturday with mild air remaining in place and a corridor of drier air aloft moving over. This will bring a breezy and warm day Saturday with many areas reaching 60 during the afternoon under a partly to mostly sunny sky. Temperatures will be cooler along the coast. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... For Saturday night, a cold front will exit the area in the evening and stall in the Gulf of Maine. There will be cold air advection after the warmest day of the year to date. H925 temperatures will fall about 12C from Saturday afternoon into early Sunday morning, but the boundary layer will be slow to cool with steady winds through the night and temperatures will stay above freezing except in the Saint John Valley and Allagash regions where temperatures may touch 32F. Temperatures will warm up quickly Sunday morning back into the mid to upper 40s north and low to mid 50s towards Bangor and the coast. The coast will benefit from the offshore winds. There will probably be some cumulus field in the morning for northern zones. However, high clouds will increase for the entire area in the afternoon as a warm front lifts northward ahead of a low pressure system in the Ohio River Valley. The clouds continue to thicken Sunday night with precipitation breaking out. The antecedent air mass is not cold. The only hope for anything but rain will be sleet in northern Aroostook due to wet bulbing as the air mass will be quite dry initially. Warm air above H850 will arrive quickly and prevent anything more than a brief period of snow at precip onset in the Saint John Valley. The sleet could last through a good part of the morning for northern Aroostook. It will remain chilly for the entire area on Monday under the steepening frontal inversion and have lowered highs for Monday...especially in the north...which will stay north of the warm front with a cool east surface flow. Tried to factor out MOS and BC guidance in favor of raw model temps. In general, the latest guidance does continues to take the surface low further west...which leads to warmer temps aloft. H925 temps will increase towards 15C along the coast by Monday afternoon. This thermal ridge...and cooling aloft ahead of an approaching upper trough...could serve as a base for elevated convection Monday afternoon in southern zones. The surface low will try to re- develop near the coast Monday afternoon...adding to the potential for convection. Overall, the low pressure system will generate about an inch of precipitation for most of the area. In terms of hydro concerns, the response from the weekend warmth and snowmelt...and then rainfall, could result in ice movement and subsequent jamming for Aroostook County rivers such as the Aroostook and Saint John by Monday. Further south, there`s less ice remaining and just a few potential trouble spots in terms of jamming. The worry by Monday night into Wednesday will be river levels rising into minor...or potentially moderate...flood levels for the rivers in the southern half of the area to include Penobscot and Piscataquis basins. Our combined T/Td thawing degree hour forecast is the highest since last April`s flooding events. Anyone with interests and/or property along the rivers in the forecast area should pay particularly close attention to developments early next week. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Colder air returns Monday night to slow melting, but temperatures will remain mostly above freezing. P-type will gradually shift to snow in the north, but not convinced amounts will be as robust as the current operational GFS. Winds will be robust on Wednesday with gusts over 30 mph likely as Monday`s low moves into the Canadian Maritimes. Cold air advection and clouds will limit Tuesday`s highs to readings not too far above the morning lows. High pressure builds Tuesday night into Wednesday. Highs return to the 40s to near 50F for Wednesday, but subfreezing temps will slow melting Tuesday and Wednesday nights. A warm front will lift northward across the region on Thursday and introduce warm and humid maritime air for Thursday night into Friday night. Heavier rainfall is possible Friday night as a deep meridional trough over the eastern US pulls moisture from the Gulf of Mexico northward towards Maine. The combination of temperatures, dew points and rainfall will renew hydro concerns Friday into Saturday. Will have to hope that the front remains progressive and does not stall over the area Friday night into Saturday. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: Conditions will lower to MVFR then IFR tonight in lowering clouds and showers. IFR conditions early Saturday morning should then improve to MVFR by mid morning then VFR by midday as drier air moves in. SHORT TERM: Expect predominately VFR conditions Saturday night into Sunday evening. Conditions will deteriorate to IFR cigs and tempo IFR vis in rain/snow and sleet early Monday morning. Snow and sleet exit the forecast by Monday afternoon, but IFR cigs and rain remains. Embedded thunderstorms towards BGR and BHB are within the realm of possibilities Monday afternoon. Conditions improve to VFR for Tuesday into Wednesday with the exception of MVFR cigs tempo IFR snowshowers north of HUL and GNR on Tuesday. && .MARINE... NEAR TERM: A SCA will be up from late this evening through Saturday for southwesterly winds increasing to 25 kt. Some patchy fog is possible over the waters late tonight into early Saturday morning. SHORT TERM: SCA conditions are possible Monday into Tuesday on the waters. Fog may accompany the winds later Monday, but lift Monday night. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 8 PM EDT Saturday for ANZ050>052. && $$ Near Term...Bloomer/Duda Short Term...MCW Long Term...MCW Aviation...Bloomer/Duda/MCW Marine...Bloomer/Duda/MCW
Area Forecast Discussion
National Weather Service Hastings NE
652 PM CDT Fri Apr 12 2019 .SHORT TERM...(This evening through Saturday) Issued at 326 PM CDT Fri Apr 12 2019 Aloft: A longwave trof extended from MT-AZ with ridges along the E and W coasts...per RAP dynamic tropopause analyses and aircraft obs. The low that affected the rgn Thu was lifting out of the mean trof to LkSup. A shrtwv trof was at its base just S of AZ/NM. Cyclonic WNW flow over NEB/KS back to SW and become anticyclonic tonight into the LkSup low heads into Canada and the shrtwv trof moves out of MX into TX and strengthens. Meanwhile... the Wrn longwave trof will move E to the High Plns by 00Z/Sun. Surface: The influence of the cyclonic flow lingering over the rgn was dcrsg with a strip of wk high pres building in. Anticyclogenesis will occur over NEB tonight...with the high strengthening overhead. This high will drift N into SD tomorrow as strong low pres moves acrs TX. Rest of this afternoon: Chilly with NW winds gusting 30-40 mph pushing WCI`s into the upr 20s at times. Plenty of stratocu in the linger cold air...espcly N of Hwy 6. Cld depths will be aprchg their peak and some of the most robust stratocu could produce some sprinkles/ flurries. Diurnal clds will rapidly dissipate in the 1-2 hrs prior to sunset. Tonight: Winds will drop off early. Mstly clr to start...but probably turning p/cldy S of Hwy 6 as mdl X-sections show some potential for mid-lvl clds. They`ve been on satellite all day over Wrn KS/Ern CO. Cold with lows in the 20s. Sat: Becoming mstly cldy as a large shield of cirrostratus moves into the area from the TX system. Warmer than today but still 10F cooler than normal. .LONG TERM...(Saturday night through Friday) Issued at 326 PM CDT Fri Apr 12 2019 Aloft: The flow will temporarily deamplify. A low-amplitude shrtwv rdg will move thru Sun with zonal flow Mon. A strong shrtwv trof will move onshore in the W Mon night. The flow will amplify as it moves inland and digs...with winds backing to SW here on the Cntrl Plns. This trof will move thru Wed. Mdls are fcstg lee cyclogenesis. The 500 mb low is fcst SW-NE acrs KS. Highly- amplified NNW flow will linger into Thu-Fri. Surface: High pres will drift E of the rgn Sun while low pres forms over AB with a cool front advancing thru the Wrn USA. Downslope warming will induce warm frontogenesis from ND-TX. This warm front will lift acrs the CWA Mon while the wk cool front advances into Nrn Plns. The cool front will move thru Mon night and become stationary acrs KS Tue...anchored by a new lee low fcst to form over CO. This low is fcst to eject acrs KS/NEB Tue night into Wed...but there is considerable spread among the last 2 runs of global mdls on location /timing. This has important implications for how far the warm sector lifts N...instability/svr wx...and dare I say snow potential Wed night. See below. The rgn will be in the cold sector Thu as low pres departs to the NE. High pres should build in Fri. Temps: Inching back close to normal Sun...but trimmed temps NW 1/3 for remaining snow cover. Warmer than normal Mon-Tue by about 10F. Wed very uncertain. It could be incredibly cool (highs in the 40s) if the warm front and low remain S of the CWA...or some 70s could occur over the SE 1/2. Thu-Fri cooler than normal. Precip: There could be some sprinkles along and N of I-80 Sun night. Probs are not high enough to include in the fcst...but we may need to add them when this period gets into the short-term. Some more sprinkles could also occur N of I-80 Mon night as well. Then we await the system for Tue night-Wed night. The lack of consensus on the storm track precludes providing any details. We will be watching potential for svr tstms ahead of the system and possibly some wraparound snow as temps cool Wed night. There will be potential for high winds as well. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 625 PM CDT Fri Apr 12 2019 VFR conditions are expected to continue throughout the TAF valid period. The wind will die down this evening and could become light and variable at times Saturday morning before eventually becoming northerly by late morning. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Wesely
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1040 PM EDT Fri Apr 12 2019 .SYNOPSIS... A weak cold front will stall across the region through Saturday maintaining a chance of showers and storms. A stronger system will bring more widespread storms to the area on Sunday and Sunday night, with severe weather possible. The weather will improve significantly through mid-week next week, with the next system expected Thursday through Friday. && .NEAR TERM /THROUGH SATURDAY/... As of 1030 PM...As the HRRR has been advertising, convection continues to struggle to redevelop across the CWA this evening. PoPs were tweaked to reflect the trends. Still expect some uptick in showers late tonight. Temps are on track, mainly in the 60s to lower 70s and falling slowly. Later tonight, a cold front will sag SE into the area, stalling roughly along the I-40 corridor by daybreak Saturday. A light S/SWLY in the low-levels will likely trigger some showers late tonight thru Saturday morning, as isent lift increases on the south side of the stalled frontal zone. PoPs ramp up to the chc range for most of the area. Thunder chances look low overnight. Unless training of showers develops, the hydro risk still appears fairly low. Low temps will be above normal under mostly cloudy to cloudy skies. Convective coverage will be hard to pin down for Saturday, with differential heating and instability best in the southeast part, but possibly more lingering boundary interaction in the northwest half, and returning SE upslope flow affecting the Blue Ridge late day. Instability could become very robust on Saturday afternoon, with some 2000 to 3000 J/kg sbCAPE possible with any heating given the high dewpoints in the 60s and slightly cooling temperatures aloft ahead of the central CONUS trough. Strengthening mid-level flow will permit deep layer shear to gradually increase through the period, but speeds in the lower 3 km of the atmosphere should not get especially impressive until just past the near term. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM EDT Friday: The focus of the short term period remains the potential for severe weather on Sunday, currently highlighted by the SPC Enhanced Risk that extends well into the CWFA, encircled by the Slight and Marginal Risks that cover the balance of the forecast area. There remains little doubt that a very good dynamic set-up for severe weather will be in place Sunday. A deep upper trough will pinch off over the deep south and encourage rapid surface cyclogenesis later during the day on Saturday. The low will translate rapidly northeast Saturday overnight, placing our area squarely in the warm sector on Sunday. Stout low-level southeasterly flow will allow surface dew points to increase to the mid 60s, and temperatures will likely rise to the low to mid 70s across the SC Upstate and NC/SC Piedmont. There will likely be an ongoing band of convection oriented north-south moving into the forecast area late Sunday morning, and though destabilization will likely not have much time to occur by that point, modest CAPE of ~500 J/kg in the far eastern portion of the forecast area may be all that is needed to maintain the line into our area. Deep layer shear will be quite plentiful, and re-invigoration of the line will be likely through the afternoon. Low-level (0-1km) directional shear isn`t fantastic, and lack of really good instability will probably support more of a cluster/linear storm mode rather than discreet cells. It does seem that the eastern portions of the forecast area will be able to destabilize more by Sunday afternoon than the rest of the area, and if the current numerical guidance is correct, ~1500 J/kg of SBCAPE could be realized by 18-21Z in the eastern SC Upstate and NC Piedmont. Around this same time, southerly 850mb flow will increase to 50kt+ in the eastern half of the forecast area, enhancing already impressive deep-layer shear profiles in the most unstable areas. All severe threats are still in play at this point, though the expected linear mode would suggest the largest threat will be for damaging winds. There is still some question as to destabilization with a previous frontal boundary laying over the forecast area Saturday through early Sunday and maintaining at least good cloud cover, if not some scattered ongoing convection. Though uncertainty in the details remains, this system is quite impressive, and bears a close watch. A quick note on a flash flood threat with this system on Sunday...convective rain rates will likely be very impressive with the line, and depending on how much rain falls on Saturday and the rates that are realized Sunday, an isolated flash flood threat could materialize across the forecast area. This will be watched as well, though high confidence in any flooding will likely be absent until Sunday afternoon. Finally, most of the severe convection should clear the area by soon after 00Z Monday, though some rain and showers could linger. The front itself will move quickly through overnight, with no pops remaining by Monday morning. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 245 PM EDT Friday: With the trough axis moving to the east, upper-level convergence will support a high pressure system propagating east Monday evening with a 1020-1024 mb centered in our region by Tuesday morning. This will set up a gorgeous Tuesday and Wednesday across our area as the upper-level ridge axis moves overhead by Wednesday morning. High temperatures will remain warm, running about 1-3 degrees above normal on Tuesday and about 4-6 degrees above normal on Wednesday with widespread 70s across the mountain valleys and points east. The lower SC and GA Piedmont may reach 80 on Wednesday. Dewpoints across the area will be very pleasant both days, in the low 40s on Tuesday, increasing into the upper 40s to lower 50s on Wednesday as return flow starts on the backside of the clockwise circulation. If you are looking to take a day or two off of work to enjoy the outdoors, this is your opportunity! The next significant weather maker ejects into the Plains for Thursday as a broad and deep longwave trough amplifies and a ~540dm 500mb closed-low is progged to move into the Midwest by Thursday night. Upslope flow shower chances are expected to increase during the day on Thursday as moist southerly flow strengthens. Despite mostly cloudy skies, highs will be similar to Wednesday within the warm sector but with higher dewpoints (upper 50s) in the return flow. The dynamics ahead of this system suggest another period of active weather for our area as the attendant cold front marches east across the Tennessee Valley while the sub-1000mb surface low pressure system occludes over the Midwest. As discussed in the previous package, being 6+ days out there remains plenty of uncertainty in the timing and the overall environment over our area. A blend of the available guidance forecasts a frontal passage later during the day next Friday, suggesting the best combination of forcing and instability will occur over the Piedmont. However, if the front passes through overnight, peak forcing will not coincide with peak instability. Nevertheless, with 0-3km bulk shear values in excess of 50 kts and 0-6km values in excess of 70kts within favorable diffluent flow, we will have to watch guidance evolution closely next week. Furthermore, a nose of 1.5"+ precipitable water values suggest deep moisture will briefly move into the region Thursday night into Friday afternoon ahead of the front as it moves through the region so any convection will produce heavy downpours that may cause significant runoff. Regardless, it`s spring and the pattern will act like it, with falling heights associated with the closed low suggesting cooler temperatures by Saturday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Despite lingering instability around KCLT, things have been fairly quiet so far early this evening. There is line of convection well to the south, that looks to track just east of KCLT later this evening. So will go with a convection-free TAF thru 06z. From there, guidance in good agreement that another round of mainly shallow showers will develop across the area, as a weak front drops south and stalls across northern NC. Moist southerly flow atop the frontal zone will produce expanding low cigs and showers thru the overnight, peaking around 12z. The front begins to lift back north and light southerly flow will persist. But there should be a lull in showers and a gradual mixing/scattering of the low cigs by early Saturday aftn. Just enough breaks in the clouds may help destabilization and a few TSRA to develop. Will go with VCSH for the early morning convection, then PROB30 for SHRA/TSRA during peak heating hours Saturday. Sfc winds will be light, mainly south to southeast, except N at KAVL late tonight thru midday Saturday. Outlook: A strong cold front will approach the area Sunday to produce the potential for stronger thunderstorms and wind gusts. Continued restrictions are highly likely from Saturday night into Sunday night ahead of and along the front. VFR conditions should return early next week behind the cold front. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 89% Med 76% High 81% High 100% KGSP High 100% Med 79% High 89% High 100% KAVL High 100% High 83% High 94% High 100% KHKY High 84% Med 77% High 87% High 100% KGMU High 100% Med 69% High 86% High 100% KAND High 100% Med 76% High 82% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JMP NEAR TERM...ARK/HG SHORT TERM...Carroll LONG TERM...JMP AVIATION...ARK
Area Forecast Discussion
National Weather Service Wilmington NC
1010 PM EDT Fri Apr 12 2019 .SYNOPSIS... Warm and humid weather will continue through the weekend with scattered showers and isolated thunderstorms. Low pressure across the Great Lakes will send a cold front across the coast late Sunday and early Monday with strong to severe thunderstorms possible. Dry high pressure will follow through mid week. A cold front will cross the Carolinas late Thursday through Friday. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 930 PM Friday...Adjustments made to overnight POPs based on latest 88D trends and HRRR output. Basically have 2 convergent areas working their way very slowly eastward. And eventually will become 1 convergent area that will eventually work it`s way east of the FA toward daybreak. The threat for thunder has pretty much diminished with the loss of daytime heating. And the dynamics associated with these convergent boundaries not strong enough alone to produce thunder. As a result, will indicate mainly RW- for the remainder of this evening and overnight. The sfc pg does relax-some overnight but enough should keep SE-S winds active enough to minimize widespread or even areas of fog. Will have to keep an eye on possible patchy sea fog that may develop especially if sfc dewpoints reach the upper 60s during Sat as winds becoming more southerly. It still may be difficult for sea fog to develop given latest SSTs having climbed into the mid 60s attm. Very little if any tweaks applied to tonights lows. Previous....................................................... As of 300 PM Friday...Rich low-level moisture (by mid April standards) is advecting onshore as a weak NW-SE oriented warm front weakens across southeastern North Carolina. This front has remained the focus for persistent clouds and showers today and is also identifiable by a 3-5 degree dewpoint difference and a 30 degree wind convergence axis. Rain has yet to fall east of the front at Wilmington or Topsail Island where lower dewpoints have kept surface parcels stable. West of the front across much of eastern South Carolina SBCAPE has risen to between 1000-2000 J/kg, but convective showers have been limited in coverage/intensity by a gradually weakening mid-level cap and substantial dry air aloft. A ribbon of deeper moisture approaching the I-95 corridor by 5 PM should support thunderstorms and possibly gusty winds. Inland convective activity appears to be largely supported by surface-based instability and should tend to dissipate after sunset. High-res convection-allowing models suggest there will be a resurgence of maritime convection overnight south of Cape Fear along the remnant front. Mid-level winds would advect any activity on to the beaches near and north of Cape Fear, where I plan to hang on to higher PoPs overnight. Some patchy fog could develop overnight, and lows should only fall to 65-67, easily 15 degrees above normal. The old warm front should be toast by Saturday morning and a straight south wind is forecast across the area. The airmass should be even a little warmer aloft, supporting inland highs in the lower 80s, with some 70s within a few miles of the beaches. SBCAPE should again rise to 1000-2000 J/kg, supporting scattered showers and thunderstorms. Although multiple upper level impulses will move northeastward across the western Carolinas throughout the day, our convection should continue to be mainly diurnal and will develop along local boundaries and outflows. Forecast PoPs Saturday range from 30 percent along the coast to 50 percent west of I-95. Convection should largely die away Saturday evening with partly cloudy conditions overnight. Saturday night`s lows in the mid to upper 60s will again be 15+ degrees above normal for the date. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 300 PM Friday...Warm and humid air mass in place ahead of approaching cold front on Sunday. Should be a quiet day to start as soundings show a deep dry layer aloft above h7, but this will change later in the aftn as air mass destabilizes more ahead of a cold front. Dewpoint temps will be in the mid 50s with strong LLJ up to 60 kts. The gradient will tighten with increasing southerly sfc winds becoming gusty through the afternoon. Aside from a stray shower early on, the main activity will ride up through the central Carolinas late aftn and will move eastward into the evening hours as deep mid to upper trough drives it toward the coast. SPC has the strongest severe potential west of local forecast area, but a marginal risk cuts through out CWA with a slight risk closer to the coast. Overall expect showers and thunderstorms to increase through late Sunday weakening some as they reach the coast by late evening. Showers will diminish overnight and by daybreak model soundings show a deep dry air mass in places. Pcp water values drop from near 1.75 Sun eve down close to half inch after daybreak Mon morning in deep cooler and drier westerly flow on the back end. Temps up near 80 on Sun will remain warm through Sun night but will begin to cool and dry heading into Monday. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 300 PM Friday...Ridge of high pressure will build in behind exiting system through Mon into Tues. Deep W-NW flow will bring unseasonably cool and dry weather Monday through Tues with plenty of Sunshine. Temps will reach into the 70s with overnight lows down to 45 to 50 most places. As the high shifts off the coast by Wed a return flow will set up with a warmer and more humid air mass returning. Expect sunshine through Wed, but should see some cu building by Thurs and potential for showers and thunderstorms by Fri as a cold front marches through the Carolinas from west to east. Should see some stronger storms with this system. Temps will warm into the 80s most places Wed through Fri with overnight lows on the warm side, remaining in the 60s. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... As of 0Z....Sub-VFR conditions to prevail through tomorrow morning as southerly flow ahead of stalled cold front to our west advects moisture into the region. Widespread MVFR ceilings will develop over the next few hours, with good chance for IFR ceilings for few hours early tomorrow morning. Not expecting widespread visibility restrictions, but brief MVFR vsbys are possible tomorrow morning at all terminals. As far as precipitation is concerned, models are indicating showers will be pretty scattered into early tomorrow afternoon and chances of rain at a particular terminal is hard to pinpoint. Have kept rain out of TAFs, but there is chance of rain at all terminals, particularly ILM, through tomorrow afternoon. Current southeast winds will become southerly overnight through end of TAF period. Extended Outlook...Showers possible both Saturday and Sunday, with isolated strong TSTMs possible late Sunday. VFR Monday through Wednesday. && .MARINE... As of 945 PM Friday...Have extended the SCA forward by 1/4 to 1/2 day due to seas being the culprit and taking slightly longer to drop below SCA thresholds. This a result of the decent SE-S fetch of the past 1-2 days. The sfc pg will generally be slowly relaxing-some thru the overnight period with winds overnight generally diminish to SE around 15 kt north of Cape Fear and S to SSE 10-15 kt south of the Cape. Will have a few convergent boundaries over the waters that produce showers late this evening that will eventually coalesce into 1 convergent boundary of showers that occasionally move northward and onshore from Cape Fear to Surf City during the overnight period. Previous................................................. As of 300 PM Friday...High pressure retreating away from the East Coast has led to a solid southeast breeze across the area over the past 24 hours. A warm front off Georgia yesterday has lifted almost to Cape Fear this afternoon. This boundary should weaken and eventually dissipate as winds veer more southerly overnight. The strongest period of winds is already behind us, and speeds should diminish to only 10 knots after midnight. Seas still averaging 6 feet nearshore in the Cape Fear area at last check should gradually subside overnight into Saturday. The Small Craft Advisory will be allowed to expire at 3 AM along the South Carolina coast, and at noon Saturday along the North Carolina coast when the last of the six-foot seas should dissipate at 20 miles from shore. Showers have largely dissipated across the coastal waters this afternoon, but are expected to redevelop overnight. Showers and even a few thunderstorms are expected to be most numerous near the dissipating warm front in the Cape Fear area. Showers should diminish again Saturday as a classic summertime seabreeze front moves inland during the daylight hours, taking most of the convection inland with it. Southerly winds will increase through Sunday with the approach of a cold front. Winds and seas will increase rapidly to advisory levels late Sun aftn into the eve. WNA showing winds up to 25 to 30 kts with higher gusts and seas up to 8 to 10 ft in the outer waters. Winds will veer around to the W after midnight as cold front crosses the waters. Winds will veer around more on Mon as high pressure builds in, diminishing down to 5 to 15 kts by Mon eve. Marine conditions will be quiet Tues into Wed as light northerly flow becomes more variable as high pressure moves closer overhead. Seas should be less than 3 ft Tues aftn through Wed. A southerly return flow will develop as high pressure shifts off the coast Tues night into Wed, remaining light through early Thurs. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...High Rip Current Risk from 6 AM EDT Saturday through Saturday evening for NCZ106-108. MARINE...Small Craft Advisory until 6 AM EDT Saturday for AMZ254-256. Small Craft Advisory until noon EDT Saturday for AMZ250-252. && $$ SYNOPSIS... NEAR TERM...DCH/TRA SHORT TERM...RGZ LONG TERM...RGZ AVIATION...VAO MARINE...
National Weather Service Jackson KY
1131 PM EDT Fri Apr 12 2019 .UPDATE... Issued at 1131 PM EDT FRI APR 12 2019 Temperatures have cooled off into the lower 50s west of I-75, where high pressure is currently centered, and where some relatively thinner high clouds reside aloft. Adjusted lows down somewhat for these areas; however, thicker high clouds should move back in overnight, thwarting much more of a drop off. Have made some minor adjustments to the hourly temperatures and dew points elsewhere to account for the trends in observations. The rest of the forecast generally remains on track. UPDATE Issued at 847 PM EDT FRI APR 12 2019 The surface cold front has worked its way east of the area, with shower and thunderstorm activity ceasing. Some of the model guidance continues to indicate a few showers possibly threatening far southeastern Kentucky after midnight. Did delay these PoPs a bit longer per the latest runs of the HRRR and NAM. Clouds will also likely hang tough tonight, with deep southwest flow remaining in place at the mid and upper levels of the atmosphere. The forecast lows look reasonable. Did readjust the diurnal curve a bit through this evening, as some locations were dropping off a a little quicker than forecast. Updates have been sent. && .SHORT TERM...(This evening through Saturday night) Issued at 342 PM EDT FRI APR 12 2019 A slow moving front continues to slow down as a deep low pressure system over the northern plains occludes. This boundary has interacted with some instability to yield a few isolated showers and storms across portions of the area this afternoon. As this instability weakens this evening, I expect much of the shower activity to diminish. There is a chance a few showers could try to get going overnight, so have kept a 20 percent chance of a shower across southeast Kentucky tonight as the boundary continues to stall out. A difficult cloud/temperatures/fog forecast tonight as the front stalls out we may keep at least some mid to high cloud around through the night. This could help keep temperatures from cratering. We also have dry advection north and west of the stalling out boundary, and this is the area more likely to see some clear skies tonight. Thus, hard to pinpoint where conditions may be most favorable for fog tonight as we have some favorable and non-favorable conditions. Thus, going to hold off on introducing any fog into the forecast and let the evening shift evaluate the need to add any fog. Temperatures will also be very dependent on where skies can clear, but will settle for low to mid 50s for most areas. Valley locations could end of colder if skies can clear out. Tomorrow, an upper level trough will move into the southern plains/Mississippi river valley region. Low level southeast flow will strengthen through the day. Given the downslope flow conditions, dry conditions will likely hold over the area despite the stalled frontal boundary lifting northward. With the downslope flow, opted to go milder for highs on Saturday with readings into the mid 70s. Dewpoints will also be quite low with MET/MAV guidance suggesting dewpoints could be between 37 and 42 across much of the area. This is much lower than inherited forecast, but does seem to make sense given the setup. This may put afternoon RH`s down under 30 percent, but surface winds should remain light enough to limit the fire danger. By Saturday night, the mid level trough axis will shift east and north towards the Ohio river valley with the eastern CONUS ridge amplifying. This will provide very mild conditions across the area Saturday night. Rain chances will likely hold off until very late as the flow will remain too southerly to allow much moisture return. Will bring in some slight chance to chance pops towards dawn to account for the approaching system. .LONG TERM...(Sunday through Friday) Issued at 445 PM EDT FRI APR 12 2019 The main forecast concern this period is with the potential for strong to severe convection Sunday afternoon to Sunday evening. The period is expected to begin with a mid and upper level trough approaching the area from the west with ridging over the Atlantic and another ridge extending into the southwest Conus. A deepening sfc low is expected to be tracking across the Lower OH Valley to begin the period with a warm front lifting north of the area and the region getting into the warm sector. There is some model variability in the strength and timing of the upper trough as it moves east as well as the strength of the sfc low tracking into OH. The 12Z NAM is stronger with the sfc low compared to the 12Z ECMWF and 12Z GFS runs by 0Z Monday. The 12Z NAM is also a bit slower with the cold front compared to much of the other guidance. Some convection may be ongoing on Sunday morning per model guidance with a midday lull in activity and the likelihood of some destabilization by mid afternoon. Wind shear will be rather strong with this system and more speed shear versus directional shear. The degree of instability is also uncertain with the GFS on the lower end nearer to 500 J/KG or less with the NAM runs more significant, but the wind fields suggest at least linear convection potential with strong to damaging wind gusts the primary threat. If more instability can be realized, some hail would also be possible. Moisture will also be sufficient enough for locally heavy rain, especially in locations that experience multiple thunderstorms. Within any lines or line segments, a QLCS tornado cannot be ruled out as well. SPC has placed the region in an enhanced risk for severe thunderstorms for this. The cold front should move across the region during the evening, with the threat for severe convection diminishing before midnight. However, the threat for showers should linger into early on Monday as the upper level trough moves into the Appalachians. Height rises in the mid and upper levels and sfc high pressure building into the region should lead to a period of drier weather from Monday afternoon into the middle of the week. Temperatures during that period will also be cooler than what has been experienced recently with most locations not expected to climb out of the 50s on Monday. Dewpoints may be sufficiently dry for a few southeastern valley locations to experience some patchy frost on Monday night as good radiational cooling should occur as the sfc high slides into the Appalachians. Unsettled weather should return during the second half of the week as the next in a series of upper lows moves from the Rockies and in the Plains at midweek and then tracks into the Great Lakes by Thu night and Friday. The associated cold front should approach East KY on Thu and move across the area by Friday morning while the axis of the mid level through should approach the area on Friday. Showers will be possible at times, with the highest chances as the cold front moves through when thunderstorms are also most probable. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 847 PM EDT FRI APR 12 2019 High pressure will gradually build in across the Ohio Valley, with VFR conditions prevailing across eastern Kentucky. Mid and high level clouds will be prevalent through the period, although some higher based cumulus ranging from 5-7k feet agl will also be seen at times. West to west northwest winds of around 5 kts will turn light and variable this evening, before becoming more east northeast at around 5 kts by late Saturday morning. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...KAS LONG TERM...JP AVIATION...GEOGERIAN
Area Forecast Discussion
National Weather Service San Francisco Bay Area
829 PM PDT Fri Apr 12 2019 .SYNOPSIS... A beautiful weekend is forecast with mostly sunny skies and temperatures in the 60s and 70s. Cooler temperatures are expected early next week with a chance of rain primarily on Monday. A robust warming trend with dry conditions develops later next week. && of 08:02 PM PDT Friday...If you liked today`s weather it was just a preview of Saturday. Building high pressure today started a noticeable warming trend around the Bay Area. Today`s warmest temperatures were felt across the interior as with highs reaching the low to mid 70s. A weak onshore flow kept the coast and Bay Shoreline cooler and mostly in the 60s, a few spots along the immediate coast stayed in the upper 50s. It`s still a little breezy, especially over the hills, but much less in the way of wind than earlier today. For tonight, latest hi-res models like the HRRR and WRF still show a possibility of patchy coastal stratus. Current forecast does bring in some coastal low clouds and at this point see no reason to remove them from the forecast. Impacts will be minimal if any. Any Saturday morning clouds will be shortlived as high pressure currently off the coast builds inland. Mostly sunny skies will prevail with an overall warming of 2 to 7 degrees across the region. The most notable warming will be across the interior with highs in the 70s to possible low 80s. Coastal area will still feel a little ocean influence limiting potential, but highs in the 60s will be pleasant. In context of climatology, Saturday`s high temperatures will be a few degrees above normal for April. Short term weather looks to remain on track and no update is needed. Temperatures will cool slightly on Sunday as the ridge flatten due to an approaching upstream system. Latest 00Z NAM still indicates a return of unsettled weather with precip moving through the region on Monday. Will need to wait for the rest of the 00Z suite, but rain on Monday is looking more likely. && .PREV of 03:00 PM PDT Friday... Saturday should be a beautiful day with mostly clear to partly cloudy skies, a slight to locally moderate warming trend over today, lighter winds, especially away from the coast, and dry conditions. The influence of the ridge will weaken on Sunday as predominately quasizonal to weak WNW flow develops aloft -- heralding a return of near neutral/normal conditions for the region. Periods of more unsettled weather will occur during this timeframe in response to a series of disturbances of varying strength will pass near and to the north of the area. The most impactful of these disturbances arrives between late Sunday night through early Tuesday morning and will bring with them a slight chance to chance of light rain showers for most of the region. Due to the fact this is a series of weaker impulses rather than a more organized single storm system, there exists some uncertainty regarding the exact timing and coverage of any rain during this time frame. Total rain accumulations should remain close to a few to several hundredths for most areas, though a few of the wettest showers could bring up to 0.10-0.15" for localized portions of the North Bay. Then, a more robust warming trend is expected to set up late next week. Models have been showing increasingly warm temperatures with each model run, particularly on what is expected to be the hottest day next week -- Thursday. This is not unusual with anomalously warm events that push beyond certain thresholds as the models have a tenacity to underforecast more highly anomalous events due to their bias towards a steady state and previous events (in which most are not highly anomalous). As a result, we as forecasters generally nudge the data slightly higher once we approach standard deviations of around 2.5-3.0. The latest confidence toolkit data (an internal tool we use to analyze anomalous patterns) indicates a +2.9-3.1 std temperature anomaly meaning that we should expect the forecast model data to underestimate the true conditions. As such, the latest forecast package has been nudged slightly upward over raw blended model output. The forecast data may continue to increase as the strength of the ridge and timing of the ridge apex comes into better focus of the shorter term, higher resolution models. As such, can not rule out temperatures on Thursday pushing into the upper 80s or even around 90 for the warmest inland locations. Elsewhere, expect inland temperatures in the low to mid 80s, and widespread upper 60s to upper 70s along the coast. Friday will be slightly cooler near the coast but could be even a tad warmer farther eastward/inland, depending on the timing of the ridge. Either way, stay tuned as the extended forecast comes into better focus! && of 5:12 PM PDT Friday...VFR except MVFR visibilities in spots along the immediate coast due to patchy haze. Sea surface temperatures (SSTs) aob April normals per recent upwelling, buoy reports SSTs ranging from 51 F to 54 F; visible sat imagery shows a few stratus patches vicinity Monterey Peninsula to Point Sur otherwise it`s clear. The 18z NAM initialized pressure gradients well, but the NAM/WRF/HRRR surface and boundary layer relative humidity fields were initialized too high and continue over-forecast at the current hour. Low to mid level thermal and height ridging generally increases through the period thus increasing stability with surface winds decreasing by mid evening. Scaled back a bit, but still leaning the 00z KMRY and KSNS tafs toward possible patchy coastal stratus nearby the terminals early Saturday morning, otherwise terminal forecasts are near high confidence VFR. Light E-SE winds developing tonight due to relaxation of surface pressure gradients and weak cool air drainage in the valleys under clear skies carry over into the morning hours before onshore winds resume by late Saturday morning and afternoon. Vicinity of KSFO...VFR, west wind 20 to near 30 knots until 04z then decreasing onshore wind through late evening. Light/variable wind Saturday morning, onshore wind returns near noontime, a few gusts to 25 knots beginning by 22z Saturday. Onshore winds decreasing again by 04z Saturday evening. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR, west wind 10 to 15 knots til mid evening then decreasing and becoming light/variable then light E-SE overnight. Light E-SE wind in the morning becoming onshore near 10 knots Saturday afternoon and early evening. A few patches of stratus possible early Saturday morning otherwise moderate to high confidence VFR. && of 4:40 PM PDT Friday...Strong high pressure over the eastern Pacific will keep gusty northerly winds in place through much of the weekend. These winds will result in small craft advisory conditions with steep wind waves and fresh swell. An upper level system will then move through the region on Monday gradually turning winds southerly across the coastal waters. Light to moderate northwest swell will continue through the forecast period. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Mry Bay until 9 PM && $$ PUBLIC FORECAST: MM/DRP AVIATION: Canepa MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Nashville TN
901 PM CDT Fri Apr 12 2019 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Radar this evening is showing a band of light rain stretching from northern Alabama northeastward across the Plateau counties then into eastern Kentucky. This activity appears to be associated with the 850mb cold front which has stalled out due to the approaching upper trough over west Texas. Overnight, this front and the surface stationary boundary will begin returning northward as the upper trough progresses further eastward. Lift along the boundary will promote development of additional showers and a few thunderstorms especially over our southwestern counties. Have adjusted pops based on the latest CONSShort and HRRR models. This activity should move out of Middle Tennessee Saturday morning, and majority of guidance keeps much of the area dry on Saturday afternoon and evening prior to a line of strong or severe thunderstorms moving through late Saturday night. Uncertainty remains on both timing and strength of the Saturday night activity. Some 18Z models move this line of storms across the Tennessee River as early as midnight Saturday night, while others are much later towards sunrise on Sunday. As far as intensity, MUCAPE will be on the low side at around 600 J/Kg or less, but shear will be very strong and likely enhanced due to a strengthening sub-1000mb surface low depicted moving northeastward across western TN/KY. Based on all of this, damaging winds and a couple of tornadoes appear possible in the overnight hours Saturday night, with the best chance across our southwestern counties where MUCAPE will be highest. Regardless if severe weather occurs with this event or not, it`s a good reminder that April is the most likely month for tornadoes across Middle Tennessee - so know your safe place to go ahead of time to keep you and your family safe in case of severe weather. && .AVIATION... 00Z TAF DISCUSSION. Expecting VFR conditions over the TAF period, with showers possibly bringing brief MVFR cigs at KCSV overnight. Showers look to move in after 05Z and will impact all terminals before the late morning hours. Additional chances for showers and a few thunderstorms will be possible during the afternoon and evening. Winds will transition to be more easterly around 10 knots gusting up to 20 knots at times for KBNA/KMQY/KCKV by the afternoon, and around 10 knots at KCSV. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......Shamburger AVIATION........Barnwell
Area Forecast Discussion
National Weather Service Pueblo CO
922 PM MDT Fri Apr 12 2019 .UPDATE... Issued at 911 PM MDT Fri Apr 12 2019 Showers rather slow to get going this evening, with best coverage of rain/snow along the NM border and near the Palmer Divide. Last few runs of the HRRR and 00z NAM are rather skimpy with precip overnight, especially over the Sangres where pocket of low/mid level dry air will be tough to overcome. On the plus side, soundings are at least weakly unstable with upward motion over the area through the night, though low level upslope flow wanes toward morning. Overall, suspect heavier snow accums will be spotty overnight, though a few convective bursts over the mountains, Palmer Divide and ern plains south of the Arkansas River county could lay down a quick couple of inches. In light of the downward trend in precip chances, began to lower pops and qpf at many locations overnight, with only minor tweaks to other portions of the forecast. && .SHORT TERM...(This evening through Saturday) Issued at 337 PM MDT Fri Apr 12 2019 ...Light to moderate snow accumulations in and near the mountains next 24 hours... Upper low taking shape across the desert southwest will move across New Mexico into southwest Texas by Saturday morning, while the northern stream extension of the upper trof drags across CO on Saturday. Models show a warm air advection band of precipitation taking shape across southern portions of the southeast plains this evening which lifts northward during the overnight and early morning hours. Shallow easterly upslope flow will help to spread low stratus back westward into the southeast mountains with some light snow showers expected across the plains by morning as temperatures drop below freezing. Warm ground and lack of any wind should mitigate impacts some for the lower elevations...with area most at risk for heavier accumulations across the southern Sangre De Cristo mountains and possibly into portions of the southern I-25 corridor from Walsenburg to Trinidad. QPF fields from models are muddied up by convective enhancement and leaned more towards a ECMWF/GFS blend to reduce some of this effect. Of course NAM with its convectively overdone QPF does indicate the potential for some local snow bursts with the convective snow showers in the afternoons. So given the suite of guidance have hoisted winter weather advisories for the southern Sangre De Cristo mountains, as well as the higher peaks above 10-11kft of the northern Sangre De Cristos, Wets and Pikes Peak. Getting 4 to 11 inches of snow for these areas. Best lift though will focus to the south...and am somewhat concerned that the southern I-25 corridor counties (western Las Animas and Huerfano counties) could see some pockets of advisory level snow amounts over the next 24 hours. Given lack of sustained upslope...will refrain from adding them into advisories for now. But as always, convection provides a wild card that can be difficult to account for with spring snow events like this one. Will just have to play this by ear. Activity should decrease some Saturday morning and weaken as it lifts off to the northeast. However with the upper trof axis moving across, there will still be plenty of moisture and instability for another round of convective higher elevation snow showers in the afternoon and evening over the mountains. Majority of POPs will pull westward to locations in and near the mountains for the afternoon hours. Temperatures on Saturday will remain below climo. -KT .LONG TERM...(Saturday night through Friday) Issued at 337 PM MDT Fri Apr 12 2019 Saturday night-Sunday...Moderate northwest flow aloft across the region Saturday night becomes more westerly through the day Sunday, as Saturday`s quick moving upper trough continues to translate east and flat upper level ridging builds across the Rockies. Isolated to scattered showers over and near the higher terrain late Saturday afternoon will quickly diminish through the evening with clearing skies into the overnight hours, as the subsident northwest flow takes hold. After another cool night, with lows in the teens and 20s areawide, warming aloft and downslope flow will help boost temperatures back to at and above seasonal norms on Sunday, with highs in the 60s to lower 70s across the Plains, in the 40s and 50s across the higher terrain and in the 30s at the peaks. Latest models do indicate a minor embedded wave moving across the Northern Rockies through the day, though looks to keep best precipitation chances north of the area, and have kept only slight pops in tact across the higher elevations of the Central Mountains Sunday afternoon. Sunday night-Tuesday...West to southwest flow aloft progged to increase Monday into Tuesday, ahead of a Pacific upper trough digging across the Great Basin through the day Tuesday. Increasing downslope flow will again boost temperatures back to above seasonal levels on Monday, with breezy downslope winds leading to the potential for critical fire weather conditions across portions of the Southeast Plains Monday and again on Tuesday. Dry weather across the area on Monday will give way to increasing chances of showers across the higher terrain through the day Tuesday, with the best coverage along and west of the Continental Divide. Tuesday night-Friday...Another cool and unsettled weather pattern expected through the middle of next week, as latest models continue to move this system across the area Tuesday night and Wednesday, bringing rain and higher elevation snow, to the area once again. This system remains relatively warm, as snow levels lower to between 7000-9000 feet Tuesday night, with north to northeast upslope flow behind the systems passing cold front providing enough lift for possible winter weather highlights across the Southeast Mts and higher elevations along the Raton Mesa into Wednesday morning. Cool and unsettled weather then continues through Thursday, as secondary energy is progged to dig down the backside of the system before warmer and drier weather takes hold for the end of next week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 337 PM MDT Fri Apr 12 2019 Patchy MVFR cigs this evening will gradually lower into the IFR to LIFR categories after midnight for both KCOS and KPUB. Convective showers will be possible this afternoon and early evening with a brief break before more persistent showers spread in after midnight. A switch over to snow is expected at both terminals with some light accumulations of an inch or two possible on grassy surfaces. Low clouds will be slow to break on Saturday but should see rising ceilings in the afternoon with KCOS and KPUB likely staying in the BKN MVFR category into early Saturday evening. KALS will remain predominantly VFR though cigs could approach high end MVFR with VCSH Saturday afternoon. Winds at all three terminals will become light this evening and remain under 15kts through Saturday. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 9 PM MDT Saturday for COZ073>075- 080-082. && $$ UPDATE...PETERSEN SHORT TERM...KT LONG TERM...MW AVIATION...KT
Area Forecast Discussion
National Weather Service Shreveport LA
944 PM CDT Fri Apr 12 2019 .UPDATE... As expected, scattered showers and a few thunderstorms are beginning to develop near and to the south of the Interstate 20 Corridor of NE TX and N LA in an area of isentropic lift. The warm front still remains well south of our region this evening but this activity is associated with increasing low level flow with KSHV VAD Winds already peaking at near 35kts which is nearly double from just 6 hours ago. Of interest with the latest 00z NAM12 output is an area of convection the model develops late tonight across Deep East Texas, moving this feature northeastward into NW LA towards sunrise. Can`t depict anything out in the strengthening southwest flow aloft pattern so this could be some feedback in the model but the fact that the HRRR is also depicting something similar, albeit not as strong or widespread, is a bit concerning. Did notice that the progs are a little slower moving the 850mb front northward overnight into our region which may cut down on the widespread rainfall the models were depicting earlier across our northern most zones by sunrise. All this to say, beefed up pops slightly across Deep East Texas into NW LA in the 06z-12z timeframe. These storms could pose a hail threat overnight given that they will likely be elevated with the true sfc based tornado/wind threat not likely to materialize until we get the warm front and warm sector into our region from the south during the day Saturday. Did adjust temps slightly overnight as 02z temps were very close to fcst mins in the morning, especially across our eastern zones who have experienced some rainfall this evening. Otherwise, no significant changes were made to the remaining portions of the forecast. Updated forecast package out shortly...13. && .PREV DISCUSSION... /issued 550 PM CDT Fri Apr 12 2019/ AVIATION... Currently tracking scattered convection in the vicinity of the MLU terminal that is moving northeast attm. An elevated 850mb boundary will be moving northward overnight that will trigger additional scattered convection near and to the north of the I-20 terminals so have accounted for this possibility in the 00z TAF set. Otherwise, the big story will be the severe convection expected to impact our terminals during the day Saturday. MVFR ceilings will return to most terminals late tonight with VCTS through the mid morning hours. Introduced prevailing TSRA during the daytime hours on Saturday for all terminals and as a sfc low begins to eject out of Central Texas late Saturday Morning through the afternoon hours, gradient winds in the warm sector ahead of the northeastward moving low will get cranking with sustained winds near 20kts with gusts upwards of 30kts. Obviously convective winds have the potential to become much stronger but for now, have left these kind of gusts out of the 00z terminal package. Winds will quickly veer around from an easterly direction to a southerly direction on Saturday, especially across our NE TX terminals with a northwesterly directional wind shift not expected until just beyond this 00z TAF package. 13 PREV DISCUSSION... /issued 331 PM CDT Fri Apr 12 2019/ SHORT TERM.../Tonight through Saturday Night/ Clouds to increase from the south overnight as a warm front lifts north across the ArkLaTex. Southerly flow behind the warm front will advect increased moisture across the region with dewpoint values forecast to climb into the mid to to upper 60s on Saturday. Also, an enhanced surface pressure gradient will generate south winds around 15 to 20 MPH by mid-morning Saturday. Mid to upper- level trough translating east across Texas will merge with frontal boundary allowing for deep-layer sheer to increase throughout the day on Saturday. Additionally, with steep lapse rates, instability will be sufficient to allow for rapid intensification of storms. Severe weather threat will increase during the day, climaxing during the time of max surface heating and continuing through the evening hours. What will start out as an elevated severe hail threat will transition into a damaging wind and tornado threat during the afternoon as organized rotating updrafts become more prominent. Convection will spread eastward across the ArkLaTex through the evening and overnight hours. Conditions to improve during the overnight hours as storm system exits the region to the east. /05/ LONG TERM.../Sunday through Thursday Night/ The forecast period begins with model agreement that the closed upper low will be across the Missouri Valley, lifting into the Upper Great Lakes during the day on Sunday. The axis with the longwave trough of this feature will shift east of the area on Sunday, with the heaviest rainfall shifting east of the area into the Mississippi Valley early in the day. A few showers will be possible closest to the low in extreme northern Louisiana and southwestern Arkansas early on Sunday before the upper low pulls further away from the area. Sunday night through Tuesday, weak mid-level ridging aloft along with a surface high pressure system will slowly move across the area, allowing for a dry forecast across the area. By Tuesday night, the area will shift into more of a southwesterly flow aloft with a warm front lifting into the region. This will allow for the return of showers and thunderstorms Tuesday night. Wednesday looks to be the next active weather day after our Saturday event, however there still is some model inconsistencies with the timing and strength of the system. It is possible that this feature will return severe weather to the area as the next upper trough moves across the southern Plains on Wednesday and into the ArkLaTex by Wednesday night. Ahead of the feature, strong instability and moderate shear in the warm sector will bring the potential threat of tornadoes, large hail, and damaging winds to the area. The chance of showers and thunderstorms will linger until early Thursday when a cold front crosses the region. For temperatures, in the wake of the front, highs on Sunday will be about 10 degrees below normal in the 60s across much of the area. With more abundant sunshine Monday into Tuesday, highs will be closer to normal values in the mid to upper 70s across much of the area. As a warm front lifts into the area, temperatures will warm into the upper 70s to lower 80s across the area Wednesday. Behind that system, highs will be near 70 across much of the area on Thursday. 04-Woodrum && .PRELIMINARY POINT TEMPS/POPS... SHV 59 74 49 64 / 70 100 60 10 MLU 59 76 55 64 / 50 100 80 20 DEQ 52 62 43 63 / 70 100 80 20 TXK 55 65 47 62 / 70 100 70 20 ELD 57 71 50 61 / 60 100 80 20 TYR 59 72 45 65 / 70 100 40 10 GGG 58 74 46 64 / 70 100 50 10 LFK 63 79 48 68 / 70 100 20 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/99