Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/06/17

See below for an aviation forecast discussion for the 00Z TAFs.

&& .SHORT TERM...(This Evening through Tuesday Night) Issued at 349 PM CST Sun Mar 5 2017 While temperatures have topped out in the 60s and afternoon humidity has fallen below 20%, most area winds are only in the 10 to 20 mph range. As such the fire weather headlines have been cancelled. Main focus remains on the strong low pressure system that develops across North Dakota for Monday. GEFS mean sea level pressure anomalies with this feature are 4-5 standard deviations below climo which is the reason we are expecting such strong winds, although the GFS is on the lower end of the spectrum when it comes to MSLP compared to the NAM/Canadian guidance. Regardless this will be a strong wind producer. Initially the strongest winds will actually be across the Coteau with pressure falls of 10mb and 1/2km winds of 50kts. While not the best mixing conditions these two factors will result in strong sustained southerly wind in the morning which may reach advisory criteria. By mid day this core of strongest wind will pass to the east. Timing on post frontal winds is still variable between guidance. Despite weak cold advection in the post frontal environment, pressure rises of 10-14mb/6 hours and 1/2km winds between 50 and 65kts suggests most of the area will have some location reach high wind criteria. The core of strongest winds does seem to make a rapid jump across the CWA between 21Z-00Z according to the GFS but it takes that model between 18Z-21Z to cross our Missouri river counties. The NAM/Canadian are more progressive but with weaker 1/2km winds which fits with the differences between the surface pressure. Winds will remain steady overnight with a gradient and pressure rises. Mixed winds going into Tuesday remain quite strong with very steep low level lapse rates. While not included in the forecast, mulled over adding some diabatically driven snow showers to boot. .LONG TERM...(Wednesday through Sunday) Issued at 349 PM CST Sun Mar 5 2017 Main challenge in the extended period will be precipitation chances, with a couple of systems forecast to move across the area. High pressure will be over the area Wednesday, then gets pushed east by a low pressure system approaching from the west. May see a few rain/snow showers across the northern CWA Wednesday night into Thursday morning with little in the way of significant accumulations. Will see a brief respite in precipitation Thursday afternoon, then another system begins to move in from the southwest, bringing decent chances of precipitation late Thursday night through Friday night, with a couple of inches of snow accumulation not out of the question. The models are not in great agreement after that, but a few of them do show the potential for yet another system toward the latter half of next weekend. Will introduce high chance pops on Sunday for now, with changes likely to come in the next several days. Will see a gradual cooling trend through the extended period, from highs in the mid 30s to lower 50s Wednesday, to highs in the mid 20s to mid 30s on Sunday. After a night with lows in the 20s Wednesday night, overnight lows will generally be in the teens the rest of the period. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 550 PM CST Sun Mar 5 2017 Making a couple of changes, mainly to the KABR/KATY TAFs, given the latest short range model guidance and the continued advection of higher amounts of surface/boundary layer moisture into east central/northeast South Dakota overnight in tandem with some strong pressure falls out ahead of a surface low and cold frontal passage. Guidance is indicating the potential that some fog and/or low stratus may be developing on favorable low level south- southeasterly upslope winds over the prairie coteau later tonight after 06z including at KATY. Further north and west, KABR will be closer to a surface trof of low pressure and markedly lighter winds overnight (favors fog formation?). KABR is also expected to see less cloud cover and for a longer period of time than at KATY. Started KABR out with an MVFR ceiling later tonight and will begin ramping up fog mention, if guidance continues to lean more in that direction for KABR. KPIR and KMBG are still likely to remain VFR all the way through to Monday afternoon before any potential caa/mixing stratus or strato-cu starts to show up. Something else that short range, hi-resolution models are hinting at is the potential for some moderately strong elevated convection by late tonight persisting through early Monday afternoon out ahead of and in conjunction with the strong cold frontal passage forecast on Monday. If trends in placement/timing of convection begin to line up better in the short range guidance, will work to introduce some sort of thunder mention at whichever TAF site confidence is highest. By early afternoon, the front should be east of KPIR and KMBG with the potential for some very strong west-northwest winds to develop there for the rest of the day into the overnight hours. It takes a little while longer for this strong front to pass the KABR/KATY terminals. But, when it does, the same can be expected there; namely very strong westerly winds. There is also the potential for some post-frontal rain/snow showers Monday afternoon through late Monday evening behind this strong cold frontal passage. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...High Wind Warning from noon CST /11 AM MST/ to 9 PM CST /8 PM MST/ Monday for SDZ003-004-009-015-016-033>035-045-048-051. High Wind Watch from Monday evening through Tuesday afternoon for SDZ005>008-010-011-017>023-036-037. MN...High Wind Watch from Monday evening through Tuesday afternoon for MNZ039-046. && $$ UPDATE...Dorn SHORT TERM...Connelly LONG TERM...Parkin AVIATION...Dorn
Area Forecast Discussion...Updated
National Weather Service Billings MT
840 PM MST Sun Mar 5 2017 .UPDATE... Made another update to push the winter weather advisory farther west into Rosebud, Treasure and northern Big Horn counties. Radar shows showers developing quickly. High resolution captures this and lingers strong returns over these areas tonight. The question will be how quickly will the rain showers change to snow. Should happen pretty quick with cold air rushing in and low dewpoint temperatures. Yellowstone county will be tricky as the eastern part of the county may pick up advisory type of weather, but only expecting around an inch over the western part of the county. Midnight crew will need to monitor Yellowstone county closely. Did raise PoPs again for central zones to account for the above. TWH && .SHORT TERM...valid for Mon and Tue... Dynamic 24 hours expected as a strong cold front will sweep through the area tonight with very strong winds behind it. Ahead of the front airmass is mostly dry but becoming unstable facilitating deep mixing. Just to the west snow is as far east as Dillon with temperatures in the 20s in Lewistown. Upper trough over the Pacific Northwest with strong shortwave passing through the base of the trough in northern CA with height falls causing surface pressure falls across central Montana. Front to the west will jump into this surface trough later this evening and the approaching shortwave from the southwest will trigger another round of pressure falls over northern Wyoming and southeast Montana later tonight. Bottom line is front causes a significant transition across the area tonight and the second round of pressure falls spins up a focused area of precipitation and increased wind over later tonight and early Monday for eastern areas. HRRR guidance shows visibilities dropping quickly along the front tonight as it make the jump into south central Montana but do expect warm ground to limit snowfall amounts. Will be a dramatic period when the front arrives and strong northwest winds combine with brief heavy snow. Further east temperatures will be cooler as the precipitation intensifies allow for better chances for accumulations. Pressure rises increase from the west late tonight with strong cold air advection with 850mb winds over 50kts for southeast Montana and southern Big Horn County and Sheridan County. Winds look to be strongest in Sheridan County and have issued a high wind warning with LAMP guidance showing multiple hours with wind gusts in excess of 60 mph. Better precipitation amounts expected as far west as Rosebud County but think early precipitation will be rain with warm ground decreasing accumulations amounts. Combination of snow and wind over southeast Montana will cause difficult travel late tonight and early Monday. Tuesday is a quieter day as heights rise and the airmass dries out and winds decrease. Temperatures will still be cooler and remain in the 40s with some mountain snow showers. borsum .LONG TERM...valid for Wed...Thu...Fri...Sat...Sun... Major changes were not needed to the long term forecast. The main area of concern in the long term period, beginning Wednesday, will be periods of snow. Upper level flow through most of next week will be westerly, with a good feed of pacific moisture embedded in the flow. Cold arctic air entrenched over Canada will move south into eastern Montana, and central zones such as Billings and Roundup, as a large upper level low over the Hudson Bay forces this air south and west. While confidence is high regarding the general circulation pattern over our region, snow amounts and locations will vary based on how far this arctic boundary can slip into Montana. The EC is not as aggressive with this boundary, and thus was a little drier and warmer through most of next week, and kept the snow over northern Montana. The GFS has this boundary much further south and west into Montana, with much better moisture overrunning this arctic boundary. Kept a chance of snow in the forecast each day through next week until details become more clear. For temperatures took a mostly even blend, though this will all depend where the arctic boundary sets up next week. Dobbs && .AVIATION... A cold front has crossed through KLVM, KBIL, and KMLS, with gusty northwest winds, showers, and periodically reduced flight conditions. The front will bring a transitions from gusty SW winds to west and northwest winds behind the front, along with increasing rain/snow showers to KSHR by 06z, and through the remained of southeast montana by ~10z. VFR conditions continue to prevail across the region, but are expected to transition to MVFR/IFR through the remainder of the evening and overnight as the cold front continues eastward. Mountain obscurations will persist through Monday afternoon as the storm system intensifies over eastern Montana. Expect to see very strong wind gusts from KBIL east to KMLS, KSHR, and the Dakotas by 12z Monday, with gusts reaching 35 to 50 kts. Higher gusts are expected east of KSHR. AAG && .PRELIMINARY POINT TEMP/POPS... Mon Tue Wed Thu Fri Sat Sun ----------------------------------------------------------- BIL 029/042 025/043 027/051 029/043 014/028 012/033 009/026 63/S 11/N 22/W 33/O 64/S 33/S 33/S LVM 020/034 020/036 028/047 033/045 021/036 023/037 017/033 53/S 22/J 24/W 53/R 65/S 44/S 34/S HDN 025/043 022/042 021/050 026/043 012/031 011/033 009/028 85/S 11/N 22/W 33/O 54/S 43/S 33/S MLS 028/041 023/038 020/045 025/038 010/024 011/028 007/022 78/S 10/N 12/W 53/S 54/S 33/S 33/S 4BQ 027/041 022/039 020/051 025/046 015/034 015/037 013/030 68/S 10/N 01/E 33/O 64/S 43/S 34/S BHK 027/037 021/034 015/042 022/034 006/022 008/027 004/021 57/S 10/N 01/E 43/S 65/S 33/S 23/S SHR 026/037 019/039 020/052 030/049 018/041 019/041 017/034 86/S 11/N 11/B 22/R 23/S 33/S 34/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory in effect from midnight tonight to 3 PM MST Monday FOR ZONES 30>33-36-37-57. High Wind Warning in effect from midnight tonight to 2 PM MST Monday FOR ZONES 38-58. WY...High Wind Warning in effect from midnight tonight to 2 PM MST Monday FOR ZONE 99. && $$
Area Forecast Discussion
National Weather Service Hastings NE
515 PM CST Sun Mar 5 2017 .SHORT TERM...(This evening through Monday) Issued at 347 PM CST Sun Mar 5 2017 Aloft: SW flow will cont overhead thru tomorrow as a deep (-2 sigma) trof progresses thru the Wrn USA. This trof will be just W of the fcst area (FA) at 00Z/Tue. Surface: Strong 1040 mb high pres was over Ern Canada with deepening 991 mb low pres over MT. This low was along a strong cool front making its way thru the Wrn USA. A broad warm sector was over the Plns. The low will deepen further as it heads across the Dakota`s into Srn Manitoba tomorrow. The FA will remain in the warm sector until the cool front emerges onto the Plns and crosses the rgn tomorrow. This Afternoon: RFW was cancelled at midday. RH`s were not going to be low enough where winds were highest...and winds were not going to be high enough where RH was lowest. P-M/cldy until sunset. Thick cirrostratus was moving thru. So sky cover was increased. Tonight: Becoming m/cldy. Very mild. Low temps will be 10-15F above normal. It will become windy for most of the FA with gusts of 30-40 mph...highest N-cntrl KS. The stratus that surged N within the plume of mstr over Ern Neb/KS last night is not far away per GOES16 vis and obs. It should move back W tonight per the 06Z/12Z NAM/GFS. The main question is how far W. The HRRR and LAMP are the best guidance with low stratus and blending them suggests no further W than Hwy 281. This has implications for aviation fcsts. Regardless of how far W it is...multi-layered mid-high clouds will still turn the sky m/cldy. Rapid clearing is expected from W-E after 3 AM. Mon: This will be on the most serious fire danger day we`ve seen since Oct 18 2012. Biggest concern is wind. A HWW was issued W of a line from Ord-Kearney-Alma and my main concern is fcst winds are not high enough and the coverage of the warning is too limited (i.e., much more of the FA could be affected by high winds vs what is currently depicted). When conds become this extreme...we as fcstrs can be too conservative because the models are not fully depicting what will occur. I compared the sfc map from 21Z Oct 28 2012 to what is fcst tomorrow and the similarities are very strong. Peak winds of 50-60 mph were widespread with 63 mph at GRI and 70 mph ODX. Wind: The 15Z HRRRX has widespread G40-45 kts with a few pixels of 50 kts at some time steps all they cross S-cntrl Neb and Rooks/ Phillips Counties in N-cntrl KS. The few times winds have been this strong since I arrived at this office...blowing dust occurred. So it`s in the fcst now. RFW conts as posted. .LONG TERM...(Monday night through Sunday) Issued at 258 PM CST Sun Mar 5 2017 Aloft: Low amplitude WNW flow prevails thru next Sun in the wake of the trof that moves thru Mon eve. Surface: A series of mstr-starved lows will slide SE along a front that will be oscillating over the region (NW-SE). Temps: will be up and down as the front drifts back and forth... but overall average warmer than normal. Precip: Very little or none. Tue: Another RFW will be needed. Another windy day...but not as windy as Mon. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday evening) Issued at 511 PM CST Sun Mar 5 2017 Main concern for aviation for this period will be winds. Breezy conditions are expected to continue through the night and on Monday expect there to be strong west winds. Have maintained some low level wind shear late tonight before the winds increase even more during the day. During the afternoon, there could be some blowing dust reducing visibility. && .FIRE WEATHER... Issued at 258 PM CST Sun Mar 5 2017 RFW conts as posted for the entire area Mon. This will be the most serious fire danger day we`ve seen since probably Oct 17-18 2012. W winds will gust 45-55 mph...possibly higher in a few spots over S-cntrl Neb. Tue another Red Flag day. Light winds Wed. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Red Flag Warning from noon to 8 PM CST Monday for NEZ039>041- 046>049-060>064-072>077-082>087. High Wind Warning from 9 AM to 7 PM CST Monday for NEZ039-046- 060-061-072-073-082-083. KS...Red Flag Warning from noon to 8 PM CST Monday for KSZ005>007- 017>019. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...JCB FIRE WEATHER...Kelley
Area Forecast Discussion
National Weather Service Houston/Galveston TX
939 PM CST Sun Mar 5 2017 .UPDATE... Most shower activity has shifted northeast of the Houston metro this evening as low level forcing from a jet streak located around 925-850 MB and weak mid-level forcing from a shortwave trough moves away from the region. However, scattered shower activity continues to develop along a low level convergence zone stretching from Matagorda Bay north towards Caldwell. Have adjusted rain chances for this evening to reflect current radar trends as well as to add a mention isolated to scattered showers across Southeast Texas through the night as a 35-40 knot low level jet expands across the region. While overall cell motion tonight should help mitigate against a widespread heavy rain threat (moving about 25 MPH per latest radar trends), will have to keep an eye on radar trends for any training that occurs with the KHGX VAD showing a fairly unidirectional wind profile and precipitable water values forecast to remain between 1.2 and 1.5 inches. Would also not be surprised to see a few 30-40 MPH wind gusts as heavier downpours are able to transport winds associated with the low level jet to the surface. Minor forecast adjustments were also made to temperatures and dew points based on observations. Huffman && .PREV DISCUSSION... /ISSUED 550 PM CST Sun Mar 5 2017/ AVIATION... Cells continue to train across SE TX and the latest HRRR and RAP keeps things active for the next couple of hours. The s/wv responsible for the rain has moved east but a weak low level convergence zone and a plume of deeper moisture will keep intermittent showers in the forecast for the next 24 hours. Still expecting MVFR cigs overnight and intermittent cigs falling into IFR. Winds look strong enough tonight to limit the fog threat. 43 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 65 81 64 74 53 / 30 30 20 60 10 Houston (IAH) 65 81 68 77 56 / 70 30 20 60 20 Galveston (GLS) 67 75 69 75 61 / 30 30 20 60 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...Small Craft Advisory until 4 AM CST Monday for the following zones: Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM...Waters from High Island to Freeport from 20 to 60 NM. SMALL CRAFT SHOULD EXERCISE CAUTION until 4 AM CST Monday for the following zones: Coastal waters from High Island to Freeport out 20 NM...Galveston Bay. && $$ Discussion...14
Area Forecast Discussion
National Weather Service Lincoln IL
912 PM CST Sun Mar 5 2017 .UPDATE... Issued at 912 PM CST Sun Mar 5 2017 Lots of clouds over the area this evening and am expecting this to continue during the overnight hours. Cloud cover and gusty winds will keep temps from dropping too much more than what they have already fallen to. Gusty winds will also continue overnight. Therefore current forecast is handling current situation well. No update planned at this time. && .SHORT TERM...(This evening through Monday) ISSUED AT 300 PM CST Sun Mar 5 2017 Strong southerly winds of 15-30 mph and gusts of 25-40 mph prevailed this afternoon across central IL and will continue Monday ahead of an approaching cold front. These strong southerly winds gave milder temperatures in the mid 50s to mid 60s, despite mostly cloudy skies. Weakening 1038 mb high pressure over central Quebec and ridging southward toward eastern VA/NC. Deepening 992 mb surface low pressure was over central MT. Latest forecast models deepen surface low pressure of 975 mb over ne ND by sunset Monday while bringing a cold front east across western IA and nw MO. Increasing low level moisture into IL ahead of this front with persistent strong southerly flow. This will bring small chances of light rain showers into southeast IL overnight and across CWA during Monday morning. Continued chances of thunderstorms over areas west of I-57 Mon afternoon, mainly late. Milder lows tonight in the upper 40s and lower 50s, which is a few degrees above normal highs for early March. Mild highs Monday in the mid to upper 60s with west central IL near 70F. .LONG TERM...(Monday night through Sunday) ISSUED AT 300 PM CST Sun Mar 5 2017 Showers and thunderstorms will be in the area to start the period ahead of a cold front that will be approaching western Illinois at 00Z Tuesday. The showers and storms will be most widespread across the forecast area during the evening, but will begin to taper off from northwest to southeast overnight in the wake of the cold front. Recent model runs suggest a few severe storms are possible, mainly Monday evening, with pre-frontal bulk shear values of 50-60 kts and MU CAPE values possibly reaching 1000 j/kg or a little higher. The best chances will occur over west-central Illinois where the instability will be higher. Locally heavy rainfall is also a threat with precipitable water values of 1.25-1.5 inches ahead of the front. The rainfall threat will quickly come to an end Tuesday morning, if it has not already done so, as the front races to the east. Gusty westerly winds are expected in the wake of the front Tuesday, with gusts to 40 mph possible by Tuesday afternoon. Forecast soundings suggest fairly deep mixing will develop to support these wind gusts, but this will also likely result in low Relative Humidity values in the afternoon. We`ll have to watch the threat for high fire danger Tuesday afternoon if current model trends persist. The models continue to struggle with the precipitation risk for the end of the week into the weekend. A fast west-northwest flow regime aloft will be in place for most of the week behind the early week storm. Model spread and run-to-run variability has been high with the low amplitude waves expected within this pattern. The best chance for organized precipitation (mainly rain) at this point appears to be Saturday. Although a risk also exists late Thursday/Thursday night, and possibly Friday. Numerous adjustments to the current forecast will likely be needed as the low amplitude waves are better resolved by the guidance. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 543 PM CST Sun Mar 5 2017 MVFR cigs have arrived at all sites except PIA and CMI. However, CMI should get there soon given that other MTRs to the west are already MVFR. Based on HRRR forecast, PIA should see MVFR cigs starting around 02z. MVFR cigs will continue rest of the night and through tomorrow as lots of low level moisture will advect into the area from the south tonight and continue through tomorrow. Models differ on if it will be continuous or have a period of better cigs at SPI and DEC overnight. Have decided to stay continuous at all sites with cig height dropping to around 1.5kft overnight and continuing through tomorrow. Models show possible light precip in the area tomorrow so will keep the VCSH already in the TAFs. Winds will remain gusty out of the south overnight and through tomorrow. Cig heights could improve tomorrow afternoon, but models differ on this solution. Will decide how to handle for next issuance. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Auten SHORT TERM...07 LONG TERM...Bak AVIATION...Auten
National Weather Service Jackson KY
956 PM EST Sun Mar 5 2017 .UPDATE... Issued at 956 PM EST SUN MAR 5 2017 Thicker mid-level clouds are nosing in from western Kentucky, with a few light returns showing up across south central Kentucky, as isentropic lift ensues. The eastern valleys continue to drop off, with temperatures in the low 40s currently, while ridges remain in the mid 50s. Thicker clouds look to overtake the entire area after midnight, so a few upper 30s may be the low end of the cooler readings in the east. Further west, some mid 40s are currently being reported at the cooler sites. These temperatures should not cool off much more, as thicker clouds are already entrenched along and west of I-75, and look to remain so through the rest of the night. Relative humidities are still in the 20 to 30 percent range on some of the ridges in the east. Given the low level flow to remain more out of the south instead the southwest through the night, this supports delaying the POPs longer into Monday morning, especially further east. The latest 00z NAM and last several HRRR runs, have also shown a slower trend with the POPs, as the better isentropic lift remains further west. Updates will be forthcoming. UPDATE Issued at 718 PM EST SUN MAR 5 2017 Plenty of mid and high level cloud cover has moved in across the area. Relative humidity is recovering, although some of the more mixed places remain near or below 20 percent. These should recover in the next hour or two. The dry low level air as well as the southerly flow in place, have allowed for valleys to decouple, with around a 10 degree split thus far in the east. Have mainly adjusted the diurnal drop off through the night, as increased clouds, and eventually the threat of some showers, will likely mitigate the split in the western half of the forecast area. Will allow for a more sustained split in the east, given the lower POPs and thinner cloud cover. Updates will be out shortly. && .SHORT TERM...(This evening through Monday night) Issued at 346 PM EST SUN MAR 5 2017 Afternoon surface analysis shows warm front has lifted north of the region this afternoon, and this is also seen on the model theta-e mag. This has shifted winds out of the south to southwest this afternoon leading to well above average temperatures. This has also been aided by dry air mixing down and subsequently leading to teens and lower 20s for RH values this afternoon. This will lead to the potential for fire weather concerns through the evening. GOES-16 VIS is showing some AC/cirrus is moving through the region this afternoon, and did increase sky some in the Lake Cumberland region to account for this. Tonight clouds will continue to be on the increase, as an upper level disturbance advances north and east toward dawn. Overall given the lower chances felt like scattered POPs seemed best based on the low chances of measuring and higher cloud bases will play a role as well. Overall models have remained in good agreement with this including the CAMS. After this progresses north Monday a drying trend will occur in the southeast through the day, with chances of showers continuing along the western CWA border. Then all eyes turn toward the strengthening system across the Plains. The surface low becomes vertically stacked across southern Canada and a trailing cold front will approach the region toward dawn. Some showers are possible ahead of the boundary, as upper level waves ride up along base of the trough. Overall think the better chances will reside beyond the forecast period, with front expected to make it into western KY by 12Z at best based on the latest guidance. .LONG TERM...(Tuesday through Sunday) Issued at 356 PM EST SUN MAR 5 2017 The models are in fairly good agreement through Wednesday, but then diverge with significant implications by next weekend. On Tuesday, a cold front will move across the area, bringing widespread showers. Instability looks rather limited, but will carry a slight chance of thunderstorms on Tuesday which is in agreement with the latest SPC Day 3 outlook which shows general thunder across all of KY. With the passage of this cold front cooler air will overspread the area, and dry weather will prevail from Wednesday into Thursday. As we move into the latter part of the week, the GFS maintains rather zonal flow with a series of low amplitude short wave troughs bringing periods of showers, and temperatures remaining mild. However, the ECMWF shows a more amplified pattern with colder air moving into the area next weekend. In fact the 850 mb temperature differences by next weekend are 10 to 15 degrees between the GFS and the ECMWF. The operational GFS looks a little warmer than the mean of the GEFS, but even the GFS ensembles support a warmer solution than the ECMWF. The superblend and WPC support the warmer solution as well and this is what was followed. This translates to highs next Saturday and Sunday in the lower to middle 60s, with lows Saturday night mostly in the 40s to lower 50s. Will also carry thunderstorm chances for Saturday. If the ECMWF was followed we`d end up with maximum temperatures only in the 40s next weekend, and overnight lows in the 30s or upper 20s. Needless to say confidence is low in the forecast for next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 718 PM EST SUN MAR 5 2017 Clouds will increase and generally lower through the majority of the period, as moisture increases out ahead of an approaching system from the west. Will maintain VFR conditions through the forecast, although places along and west of a line from KSYM and KSME may flirt with MVFR at times between dawn and noon Monday, as showers threaten. Shower chances will likely diminish towards the end of the period, with ceilings likely raising as well. South winds at 5 to 10 kts through the mid-morning hours on Monday, will increase to around 10 kts, with gusts of 15 to 20 kts during the afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...DJ LONG TERM...SBH AVIATION...GEOGERIAN
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
928 PM CST Sun Mar 5 2017 .UPDATE... Issued at 927 PM CST Sun Mar 5 2017 Area remains cloudy at mid evening with temperatures remaining well above average for early March. Southerly winds are gusting out of the south in a tight pressure gradient. We should still begin to see scattered showers develop across southeast Missouri into southwest Illinois around midnight. Latest runs of the RAP continues to show low level moisture convergence in this area under southwesterly flow aloft. Otherwise, only made minor changes to temperatures. Britt && .SHORT TERM... (Through Late Monday Afternoon) Issued at 323 PM CST Sun Mar 5 2017 The surface pressure gradient across MO/IL will begin to tighten overnight due to a developing surface low over the northern plains. A southwesterly LLJ at H85 will develop and strengthen overnight before shifting eastward on Monday, and a jet streak aloft will also approach the area from the west. These factors will lead to windy conditions on Monday with sustained winds of at least 15-25 mph and gusts of at least 30-40 mph. Stronger gusts are possible depending on the depth of mixing on Monday, and a Wind Advisory may eventually be needed. Cloudiness is expected to persist overnight due to persistent low- level moisture advection ahead of the aforementioned low pressure system. Overnight lows will be warmer than last night due to clouds, rising dew points, and windy conditions. Monday still looks unseasonably warm with highs in the mid-60s to low 70s. Scattered SHRA/TSRA may develop on Monday afternoon ahead of an approaching cold front, but the best opportunity for widespread precipitation will be on Monday night (see below). Kanofsky .LONG TERM... (Monday Night through Next Sunday) Issued at 323 PM CST Sun Mar 5 2017 Focus at the beginning of the period is severe weather threat Mon night into Tues morning. The NAM continues to suggest more available CAPE with this system compared to the GFS along with a slower fropa. This slower soln has support from the ECMWF/local WRF, while the GFS/GEM are in better agreement. Have kept cat PoPs across some portion of the CWA overnight with fairly good coverage expected at some point. Believe the GFS convection scheme is aiding in the lower CAPE based on progd soundings. Still, given the 60+ kts LLJ ahead of the fnt, TSRA that develop will pose a wind threat. Some mdl guidance suggest TSRA developing ahead of the fnt. Believe the CAP in place shud keep any convection suppressed ahead of the approaching cdfnt. Focus then turns to a variety of issues on Tues. With a strong pres gradient, expect fairly high winds/gusts, esp during the afternoon hours as a s/w rotates around the base of the upper trof. The main focus for these winds will be across the nrn half of the CWA. The GFS suggests mixing much higher, to around 600mb, than other operational guidance. This wud suggest much higher gusts than are currently forecast. For now, have taken a middle of the road trend, which is close to the local WRF. Will need to continue to monitor winds for Tues with an Advisory being possible. With much drier air advecting into the region, will also need to monitor fire wx concerns. Winds and low RH conditions are met for nrn and wrn portions of the CWA. The only question remaining is fuel moisture. Granted, in these setups, fuel moisture drops quickly, but with the RA expected Mon night, will hold off on a Watch for now. Another focus will be max temps on Tues. Have trended warmer, but if deeper mixing does occur, going forecast is not warm enuf. Looking into the extd, have capped PoPs Thurs afternoon/evening due to a large shift in mdl guidance. Mdl differences only increase beyond and have kept PoPs in the lower chance range if not dry. Tilly && .AVIATION... (For the 00z TAFs through 00z Monday Evening) Issued at 540 PM CST Sun Mar 5 2017 Ceilings are expected to improve from MVFR to VFR this evening before decreasing back to low MVFR overnight. There may be some scattered showers across the area overnight into early Monday morning. MVFR ceilings are expected through the day on Monday. Showers and scattered thunderstorms will develop across the area on Monday afternoon. Gusty, southerly winds will continue across the area through the period. SPECIFICS FOR KSTL: Ceilings are expected to increase above 3000FT AGL by mid evening before falling back below 2000FT AGL by late tonight. MVFR ceilings are expected through the day on Monday. Showers and scattered thunderstorms are expected at the terminal on Monday evening. Gusty, southerly winds will continue through the period. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Miami FL
805 PM EST Sun Mar 5 2017 .UPDATE... The 00Z MFL sounding indicated a moist layer near 850 mb, drying the mid levels, and increasing moisture aloft. Confirming these observations, IR satellite imagery displayed low level strato- cu streaming in from the east, and scattered high cirrus clouds pushing westward over the peninsula. Sustained winds 20-25 KT were noted in the boundary layer. The main story tonight will be the breezy conditions along the east coast metro and coastal waters. For the interior, winds will decrease slightly through early morning to around 10 mph. Short term models, including the HRRR and Hi- Res WRF, prog sporadic light showers to move onshore from the Atlantic through the next several hours. Slightly increased PoP coverage inland to account for current radar trends. Otherwise, forecast appeared on track. && .PREV DISCUSSION... /issued 716 PM EST Sun Mar 5 2017/ AVIATION... VFR conditions will prevail through the period with some occasional cigs of 050-060, There still is some potential for brief MVFR with passing SHRA if any. However, coverage of showers is too sparse and light to include VCSH at this time. Winds will decrease some overnight but still remain out of the east in the 10-15 kts range. Tomorrow winds increase again around 13Z-14Z with ENE wind around 20kts with occasional gust 25-30kts. PREV DISCUSSION... /issued 404 PM EST Sun Mar 5 2017/ DISCUSSION... The 12Z MFL sounding from this morning showed sustained east northeast winds 20-30 KT from the surface to near 850 mb and west northwest wind aloft. Also of note, a moist layer at 850 mb was topped by a temperature capping inversion. Latest surface analysis indicates strong high pressure centered over Virgina, which is the feature responsible for generating the tight surface pressure gradient and strong easterly flow. The highest wind speeds have occurred along the immediate east coast metro region, where gusts from 30 to 40 have been common. Further inland, surface friction has kept winds mainly below 30 mph. GOES-16 IR satellite imagery continues to show bands of low clouds streaming east to west across the area. Hi-Res models, including the HRRR and WRF prog isolated showers to persist through this evening and into tonight, affecting the east coast metro, typical of an easterly flow pattern. However, not expecting much in the way of accumulation as forecast PWAT values remain below 1 inch. On Monday, as the aforementioned surface high edges east and out over the open mid- Atlantic ocean, winds will shift to from east northeast to east and remain breezy. Again, the strongest winds are forecast right along the immediate east coast and slightly weaker across the interior. Expect maximum temperatures Monday in the mid 70s along the eastern peninsula and near 80 degrees further west, a few degrees cooler than normal for this time of year. Tuesday, as surface high pressure continues it eastward journey, away from the CONUS, surface pressure gradients will begin to ease. This should translate to slightly weaker winds and a shift to the east southeast direction. High pressure aloft building over the area, will generate warming conditions with maximum temperatures near 80 along the east coast and lower 80s to the west. Weak instability and modest moisture in the lower levels will lead a slight chance of showers along the eastern portion of the peninsula through the period. Mid to late next week: Winds should decrease significantly on Wednesday, as surface pressure gradients weaken. With high pressure ridging dominating the synoptic weather pattern, maximum temperatures Wednesday and Thursday will be allowed to climb back into the low to mid 80s. Both the GFS and ECMWF continue to hint at another cold front approaching the area by Wednesday night/Thursday. However, this front appears to be rather weak by the time it crosses our CWA. MARINE... Small Craft Advisory remains in effect for all local waters... Wind gusts to gale force possible for offshore Gulf and Atlantic waters... Strong high pressure to the north will allow for 20-30 knot winds to continue across the local waters today, with the flow gradually veering from easterly to southeasterly with time. Gusts to gale force will be possible through tonight for the offshore Gulf and especially offshore Atlantic waters. Seas will be 5-7 feet in the offshore Gulf waters, and 7-11 feet in the Atlantic, highest in the Gulf Stream. Winds and seas will gradually decrease for the Gulf waters Tuesday morning and Atlantic waters late Tuesday. BEACH FORECAST... A High Risk of rip currents for the Atlantic beaches will continue through at least Tuesday evening with continued strong onshore flow and rough surf. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 67 76 68 79 / 20 20 20 20 Fort Lauderdale 68 76 69 78 / 20 20 20 20 Miami 67 77 68 80 / 20 20 20 20 Naples 59 80 61 82 / 0 10 0 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through Tuesday evening for FLZ168-172-173. AM...Small Craft Advisory until 7 PM EST Tuesday for AMZ630-650-651- 670-671. Small Craft Advisory until 7 AM EST Monday for AMZ610. GM...Small Craft Advisory until 7 AM EST Tuesday for GMZ656-657-676. && UPDATE...27/JT DISCUSSION...27/JT MARINE...27/JT AVIATION...52/PS BEACH FORECAST...27/JT
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
603 PM CST Sun Mar 5 2017 .SHORT TERM...(This evening through Monday) Issued at 303 PM CST Sun Mar 5 2017 Warm and moist air continues streaming in from the Gulf this afternoon as dewpoints have climbed into the upper 40s and even a dew sites have topped 50 degree dewpoints. There is quite a difference in temperatures across our forecast area this afternoon with far western MN observing temps in the mid 60s under sunny skies, while western WI has been pinned under overcast stratus with temps held in the 40s. Stratus is quickly expanding from south central MN through the metro. This trend will only continue this evening as expect further expansion of the ceilings to the west tonight. Continued to advertise fog and drizzle overnight as dewpoints in the mid 40s to 50 degrees and weak lift under the inversion try to produce drizzle. Lows tonight will obviously be very warm for this time of year given the very high dew points advancing into our area behind the warm front associated with the developing low pressure system in Montana. Much of the same will be the case tomorrow morning as we remain socked in the warm/moist sector of this system. This will certainly bare watching as the cloud cover/fog will bare impact on tomorrow`s highs (which are expected to exceed 60 degrees across most of the area), and the potential for thunderstorms along the cold front late in the day and tomorrow evening. During the day tomorrow, still anticipate showers moving through but without a focused starting point and broad lift across the area, kept the pops fairly broad and limited in the chance category until after 18Z. The deepening surface low will be pushing east across southern North Dakota tomorrow afternoon. The threat for thunder exists tomorrow afternoon, mainly in eastern MN. However, the front looks to have slowed a little bit from the previous forecast. So, the long term section below will delve more into the details of the thunder/severe potential along the cold front. .LONG TERM...(Monday night through Sunday) Issued at 303 PM CST Sun Mar 5 2017 Although the tail end of the long term period could become somewhat busy with snow (or possibly mixed precipitation) chances, the guidance remains abysmal in terms of run to run consistency and agreement between deterministic runs and ensemble members. So, focused primarily on the beginning of the long term, which will certainly be busy given chances for thunderstorms and perhaps some severe weather Monday evening along with very strong winds from then into Tuesday night. The guidance has continued to slow down the progression of Monday`s system, and most solutions now delay the cold frontal passage until the evening hours over the central and eastern portion of the area. That slower timing could allow for thunderstorm development a bit west of I-35 during the late afternoon, with some potential for severe weather as it races east through early evening. Instability will be limited, and much will depend on when we see thinning of cloud cover and/or breaks to get additional insolation and heating. The dry slot associated with the large scale system does look to precede the arrival of the surface front, and most of the guidance allows for some clearing by evening from south central Minnesota into portions of Wisconsin. Even without clearing, advection alone will get temperatures into the 60s across much of the area. Best guess is that we`ll see MLCAPE values from 250-750 J/Kg ahead of the front in the early evening. Forecast sounding indicate a good portion of this will be in the 0-3km layer. Not surprisingly, shear will be abundant, both low-level and deep layer. With 0-3 km shear on the order of 40-60 kt, oriented fairly perpendicular to storm motion, there could certainly be a wind threat with any storms that develop. The environment could also support low-topped supercells for a brief period of time, so cannot rule out the possibility of a short-lived weak tornado. Regardless of storm development and severe potential, we should see a burst of strong winds behind the front. These should calm down some overnight, allow it will certainly remain fairly windy. The strongest widespread winds still appear to be most likely on Tuesday, as we see extremely deep mixing from late morning into early evening. The GFS and NAM both suggest mixing well into the layer of 50+ kt winds, and some CAM solutions are now beginning to show this sort of gust potential. A high wind watch seems warranted from late morning Tuesday into Tuesday evening, particularly across the typically more windy western and southern areas. Much of the remainder of the area will likely need a wind advisory as things get closer in time, but since these locations could see winds exceed warning criteria a watch seems prudent. We`ll slowly see winds calm down Tuesday night and Wednesday as the system moves away from the region. From Thursday through the remainder of the forecast period there are PoPs for much of the time, but very little confidence in the details of where and exactly when the best chances for precipitation will be. As mentioned earlier, solutions have been bouncing around quite a bit from Thursday onward, and the spread apparent in the ensembles suggests there is little point in trying to pick a favorite, unless you want to wish-cast a snow storm. For the most part, however, whatever precipitation we see during that time, looks like it would be all or mostly snow given the forecast temperature profiles from the GFS, ECMWF, and Canadian. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 603 PM CST Sun Mar 5 2017 CIGS are mainly VFR to start, with main sub-VFR cloud field now crossing I-80 in central IA. Given strong low level wind fields, these clouds will not take long in getting up here and delayed arrival of MVFR CIGS to closer to a GFSlamp timing. Still expect CIGS to drop tonight, but IFR and lower cigs are currently way down in the OKC/DFW areas, so continued to be more optimistic than the HRRR with cloud heights. Though can`t rule out some dz/-ra tonight through the morning, moisture depth just doesn`t look deep enough to warrant a precip mention, so kept terminals dry. Best chance for rain looks to come along the cold front that will be blasting across MN tomorrow afternoon. 18z hi-res NAM reflectivity isn`t too far off from what we were thinking for line of TSRA development Mon afternoon. Behind this front, SW winds will be humming when looking at forecast soundings from the NAM, so really boosted wind speeds at the end of the TAF periods for RWF and MSP. KMSP...Confidence is low on precip potential late tonight through Monday morning, hence it`s removal from the 00z TAF. Our greatest window for DZ/-RA looks to be between 8z and 15z. Front looks to come through MSP right around 00z, with thunderstorms certainly possible as it comes through, so added the prob30 for TSRA with that in mind. Winds look strong Monday night through Tuesday behind the front, with significant cross wind issues looking likely during this period. /OUTLOOK FOR KMSP/ Tue...VFR and very windy. Winds W 30G45kts. Wed...VFR. Winds WNW 10-15kts. Thu...VFR. Winds NE 5-10kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...High Wind Watch from Tuesday morning through Tuesday evening for MNZ041-047-048-054>057-064-065-067-073>075-082-083-091-092. && $$ SHORT TERM...SPD LONG TERM... AVIATION...MPG
Area Forecast Discussion
National Weather Service Pueblo CO
732 PM MST Sun Mar 5 2017 .UPDATE... Issued at 719 PM MST Sun Mar 5 2017 Updated to end red flag warning for this evening. Also made some changes to the High Wind Warning, adding lower elevations of Teller County beginning tonight, and the San Luis Valley for tomorrow. For Teller County, HRRR suggests strong winds spilling down the slopes of Pike`s Peak late tonight/early Mon morning, with potential for strong winds in the Cheyenne Mountain area after midnight. Winds may be lighter farther north (i.e. Woodland Park area), though east slopes of the Ramparts will likely approach high wind criteria at times Mon morning. For the San Luis Valley, given 45 kt gusts at KALS earlier today and even stronger gradient and upper level winds forecast for Mon, 50 kt plus gusts look possible, especially late morning/early afternoon. && .SHORT TERM...(This evening through Tuesday) Issued at 322 PM MST Sun Mar 5 2017 ...Damaging Winds with High Fire Danger Southeast Mountains and Plains...Wind Driven Snow for the Continental Divide tonight through Monday... Upper trof over the Great Basin will translate eastward across Colorado tonight and Monday bringing a myriad of fire...high wind...and snow highlights to the area. Snow has already ramped up along the Continental Divide this afternoon...and this will continue through focus gradually shifts from the southwest mountains tonight, into the central mountains on Monday. Snowfall amounts will come up into the low end advisory numbers (around 4 to 8 inches) but with winds gusting up to 75 mph at times...the blowing snow will be the primary concern with impacts to travel across the high mountain passes. Winter Weather Advisories for the continental divide will continue until 6 PM Monday...but southern areas will probably be able to be cancelled a little sooner. Meanwhile...Gusty winds and low relative humidity values have resulted in Red Flag conditions across much of the southeast plains this afternoon. Its been a little slow to materialize across the far east plains but with a few more hours to go...most areas will likely verify. Will maintain the current Red Flag Warning until 7 PM. Meanwhile...upper jet is already translating in from the west with 120+kt southwesterly jet setting up across southern CO by 06z. Winds at mtn top level will increase into the 60-70kt range...and although there will be quite a bit of forward shear...especially towards 12z...we should still see a burst of high winds with the bora cold front as it moves across the mountains later tonight. Already seeing gusts up to 70 mph across some of the mountain sensors. So have hoisted High Wind Warnings beginning at 7 PM for the southeast mountains...spreading into the southern I-25 corridor (south of Colorado City) and Wet Mountain valley after 11 PM...then into the southeast plains after 6 AM. Suspect we should see some gusts up to 85 mph across the mountains...with gusts to around 60 to 65 mph across the plains. Unfortunately with such low relative humidity values we should see another day of critical fire weather conditions with dangerous fire behavior and rapid rates of fire spread possible. Thus another Red Flag Warning goes into effect at 8 AM and continues until 7 PM on Monday. Winds will gradually diminish Monday evening and snow will taper off across the mountains. Tuesday will be much quieter wind-wise across the area...though still breezy across the mountains. Conditions may come close to critical fire weather parameters across Teller and El Paso counties Tuesday afternoon...but it is expected to be be too brief for any additional fire weather highlights. -KT .LONG TERM...(Tuesday night through Sunday) Issued at 322 PM MST Sun Mar 5 2017 There is good agreement between the models and ensembles through the end of the week, but major differences Friday through the weekend. Tuesday night through Friday...zonal westerly flow is forecast across Southern Colorado during this time period. Warm temperatures are expected with 70s for highs across the Plains. Overnight lows will also remain warm with 30s to 40s. A weak wave embedded in the flow may produce isolated showers over the Central Mountains Tuesday night into Wednesday morning. Dry relative humidity values and light winds are expected to prevail through Thursday. By Friday the upper pattern begins to diverge with elevated fire weather concerns across the Plains as winds begin to increase. Saturday and Sunday...models are quite different as we head into next weekend. The GFS brings a strong upper level shortwave trough across Colorado. This would bring a much higher fire weather concern to the area Saturday, and especially on Sunday. Temperatures would remain warm with 60s and 70s across the region. In addition, snow would move into the Continental Divide on Saturday and Sunday with a cold front dropping south across the Plains Sunday evening. The ECMWF on the other hand is much different. It builds an upper ridge over Utah over the weekend. It does drop a cold front south on Saturday with cooler temperatures behind the front with 50s and 60s for highs by Sunday. This would also limit snowfall over the mountains to isolated activity over the Central Mountains only. The gradient across the area would also be much weaker with a reduced risk of fire weather conditions. We will continue to monitor the model trends over the next few days. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 322 PM MST Sun Mar 5 2017 Southwest winds will gust to around 25-35 kts in the TAF sites through 02z. Could see a window for low level wind shear in KCOS starting around 02-04z and persisting until winds pick up later in the night. As the upper jet shifts overhead...mountain top winds will increase to around 50-60 kts sustained by around 03z. Should see a surge in winds come down the eastern slopes into the TAF sites overnight 08z-10z timeframe with gusts to around 30-40 kts. Wind gusts will be a lot stronger for the mountains...with localized gusts to around 65-75 kts. Winds will shift around from the west Monday morning with sustained winds approaching 35 kts by afternoon with sporadic gusts to around 50-55 kts at times. IFR conditions will continue along the Contdvd...and should become more widespread by this evening. Widespread LIFR conditions in SN and BLSN will persist along the Contdvd through Monday. Wind in the 40-50 kt range with gusts to around 60-70 kts will be possible over the higher areas. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 6 AM to 6 PM MST Monday for COZ069>071- 083>086-089-093>099. Red Flag Warning from 8 AM to 7 PM MST Monday for COZ222-226>237. High Wind Warning from 11 PM this evening to 6 PM MST Monday for COZ078-087-088. High Wind Warning until 6 PM MST Monday for COZ072>075-079>082. Winter Weather Advisory until 6 PM MST Monday for COZ058-060-066- 068. && $$ UPDATE...PETERSEN SHORT TERM...KT LONG TERM...MOZLEY AVIATION...KT