Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/07/17

Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
915 PM CDT Thu Apr 6 2017 .SYNOPSIS... Issued at 256 PM CDT Thu Apr 6 2017 H5 analysis from earlier this morning had a closed low over south central lower Michigan. a trough of low pressure extended south of this feature to the Florida Gulf Coast. A secondary, embedded shortwave was noted across western Iowa and showed up nicely on WV imagery this afternoon. West of the trough and shortwave, a ridge of high pressure extended from southern Utah, north northeast into northern Manitoba. East of the upper low and trough, a ridge of high pressure extended north from Bermuda into the Canadian Maritimes. West of the western CONUS ridge, a trough of low pressure extended from the Gulf of Alaska south into the western Pacific-off the coast of northern California. At the surface, high pressure dominated the weather pattern across the Dakotas into central Nebraska earlier this morning. Winds were light earlier this morning, and have begun to shift to the south as high pressure pushes east into the eastern Dakotas and eastern Nebraska this afternoon. Readings as of 3 PM CDT ranged from 52 at O`Neill, to 62 at Ogallala. && .SHORT TERM...(This evening through Friday) Issued at 256 PM CDT Thu Apr 6 2017 Tonight and Friday: Near term forecast challenges are temperatures and winds on Friday. For tonight: Surface high pressure will push east into the mid Mississippi valley overnight. Southerly winds will begin to increase as this feature exits to the east, and should be in the 5 to 15 MPH range overnight. The addition of southerly winds and warm air advection behind a warm front, will give a boost to lows tonight over what was seen earlier this morning. Overnight lows will generally be in the middle to upper 30s, with the warmest readings across the northwest and sandhills, where winds are expected to be strongest across the forecast area. On Friday, southerly winds will increase by afternoon to 20 to 30 MPH with gusts appg 35 MPH in the afternoon. The latest NAM and GFS solutions do indicate good unidirectional winds to 825 MB tomorrow afternoon. Mixing to that level, yields lower 70s for North Platte Friday afternoon. The inherited forecast had a high of 70 for North Platte and felt this to be too cool based on the latest met and mav guidance which had 74 for a high at North Platte for Friday. That being said, will give a 2 to 4 degree boost to temps for Friday. .LONG TERM...(Friday night through Thursday) Issued at 256 PM CDT Thu Apr 6 2017 Mid term: Friday night through Sunday: Precipitation chances Saturday night into Sunday is the main forecast concern. Temperatures will continue their climb Friday night into Saturday as very warm H85 air pushes into western and north central Nebraska. After mild lows in the middle 40s Friday night, highs will surge into the upper 70s and lower 80s for Saturday. With readings rising into the 80s on Saturday and a dry airmass in place, minimum relative humidity will fall off to around 20 percent Saturday afternoon. Fortunately a surface trough of low pressure is expected to be anchored across western then central Nebraska on Saturday. Winds INVOF this feature will be light saturday afternoon and will help to alleviate the fire weather threat. A cold front will approach, then track through western and north central Nebraska Saturday night. The frontal passage will largely be uneventful and will be mainly a wind shift. Late Saturday night into Sunday morning, elevated instability will lift into the western forecast area overnight. H800 LI`s become negative by late evening and the model even generates some light convective precipitation in the north overnight. That being said, introduced a mention of isolated thunder in the forecast. Extended: Sunday night through Thursday: In the extended, precipitation chances Sunday night into Wednesday are the main forecast challenges. For Sunday night into Monday: An upper level trough of low pressure will lift across the northern Rockies emerging onto the high plains Sunday evening. The ECMWF and GFS solutions this morning have come into much better agreement with their track of this feature early next week. In fact, they are in good agreement this morning. That is, the models track the H500 low across southern South Dakota. On this track, the bulk of rain will fall across South Dakota into far northern Nebraska. With this in mind, pops were scaled back in the south and confined to the north. This resulted in some decent changes to the ongoing forecast. Benign conditions will set in Monday night with a second wave of low pressure to arrive Tuesday night into Wednesday. With this second system, moisture works its way into central and western Nebraska and have introduced thunderstorms in the forecast from Wednesday into Wednesday evening based on moisture return and negative LI`s as indicated in the latest GFS soln. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 616 PM CDT Thu Apr 6 2017 VFR is expected all areas tonight through Sunday afternoon. A southerly nocturnal low level jet increases to near 50kt tonight. Low level wind shear is expected in many areas. Otherwise scattered high level clouds are expected from a storm system affecting the Wrn U.S.. && .FIRE WEATHER... Issued at 914 PM CDT Thu Apr 6 2017 A blend of the HRRR models...the 1 hour GFS output and the RAP places critical fire weather conditions Friday across Zone 204...the Eastern Panhandle. Per coordination with WFO CYS...a fire weather watch has been issued for this area. && .LBF WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Friday afternoon through Friday evening for NEZ204. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...CDC FIRE WEATHER...CDC
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
635 PM CDT Thu Apr 6 2017 .SHORT TERM... 302 PM CDT Through Friday... Short term concerns center on winds, high waves, and lakeshore flooding. Bottom line up front: Wind advisories have been canceled, the lakeshore flood warning for Illinois has been canceled, we have maintained the high wind warning and lake shore flood warnings for Indiana. Widespread flooding is not expected across Illinois, but do expect minor flooding to be possible right at the lake shore. The deep and mature upper level circulation over Lake Erie will slowly move up through New England into Friday. The surface low, while still strengthening, will also pull east through the period as well. Meanwhile, surface high pressure across the upper Midwest, while not overly strong, will maintain a decent gradient across the area through this evening, especially across the lake. Winds across the Illinois side of Lake Michigan largely have held a NW direction which has minimized the build up of waves along the Illinois lakefront, though there is a mesoscale boundary draped across Cook County which is maintaining a NE component at times. Winds with this NE shift are not super strong, and therefore while minor flooding right at the immediate lake shore in Illinois is possible, did not feel a flood warning served the situation well. The story is different across NW indiana where NW winds have been able to build waves along the Indiana shoreline. RAP forecasts suggests a few hour period still today where winds can strengthen, thus the high wind warnings and lakeshore flood warnings remain in effect. This is not the time to be at the shore. On the back side of the circulation a well developed cumulus field will continue through sunset. Hi resolution guidance paints a few showers this afternoon, and thus maintained a low mention though coverage of this should remain low. High pressure will slowly nose in from the west through the night, and thus expect a gradual clearing to the skies. Forecast soundings suggest some decoupling to the winds, and thus expect winds to subside, though the may hang on a bit longer in Indiana and in the urban areas. Temperatures will fall to at or around the freezing mark tonight. On Friday the high pressure ridge will shift from Iowa at daybreak to western/central Illinois in the afternoon. Clear skies and weakening winds will be the story, along with a warm up back into the 50s. KMD && .LONG TERM... Friday night through Thursday... 218 pm...Main forecast concerns include frost potential Friday night...warm up for the weekend and next chance of showers and thunderstorms Sunday night through Monday night. A ridge of high pressure will move across the area Friday evening and with generally clear skies and light winds...some patchy frost is possible...especially across the southeast half or so of the cwa. Temperatures slowly begin to warm aloft overnight along with increasing high/mid confidence on how widespread the frost becomes is low. Maintained frost mention in the grids/zfp but some tweaks/changes are possible with later forecasts. Breezy southerly winds will develop Saturday and continue on Sunday as high temps will warm well into the 60s on Saturday and into the lower...perhaps mid 70s on Sunday. Wind directions should prevent a lake breeze with the warmer temps all the way to the lake shore. Low pressure will move across the north central plains Sunday into Sunday night and eventually to the northern Great Lakes region by Monday night. Models appear to be converging on a solution with an upper wave moving across the area Sunday night and this looks to be the best chance of showers and a few thunderstorms. For now have stayed dry Sunday and after this wave moves through...much of Monday could be dry with a second wave possibly allowing additional showers and thunderstorms to develop Monday afternoon into Monday evening. Confidence is still rather low regarding how this system evolves but trends do seem to be emerging. High temps on Monday likely to still be least in the 60s and possibly higher depending clouds/morning precip. Another ridge of high pressure will move across the area midweek with another system moving across the region Wednesday night into Thursday. This timing is faster than previously shown from the models so confidence on this system/timing is also low. cms && .AVIATION... For the 00Z TAFs... Only aviation forecast challenge this TAF cycle is winds. Lake breeze moved through ORD/MDW late in the afternoon, but with time lake influence should wane this evening and winds trend back to west of due north. Timing of the switch to west of due north of low confidence. Gustiness should abate this evening, though an occasional gust up to 20kt is possible tonight into Friday morning, gustiness should be the exception, not the rule. As northwest winds begin to ease Friday afternoon it should allow for the development of a lake breeze, which will likely result in a wind shift to northeast late in the afternoon. Izzi && .MARINE... 320 pm...Strong low pressure over Pennsylvania will move northeast across New England tonight and into Quebec Sunday. At the same time...high pressure extending from southern Canada to the central plains will move southeast tonight into Friday...eventually reaching the Gulf of Mexico coast. The gradient will remain strong between these two systems...but slowly begin to weaken overnight into Friday morning. Gales will slowly end from north to south late tonight into Friday morning. A weaker ridge will extend north from the high and will move across the lake Friday afternoon into Friday evening with a period of light winds which will shift southerly Saturday and begin to increase with speeds possibly increasing to 30 kt. These southerly winds will shift southwesterly as low pressure moves from the central plains Sunday to the northern lakes region Monday. After this low passes...a cold front will likely shift winds northerly Tuesday into Tuesday night. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...Lakeshore Flood Warning...INZ001-INZ002 until 1 AM Friday. LM...Gale Warning...IL nearshore waters until 5 AM Friday. Gale Warning...LMZ743-LMZ744-LMZ745-LMZ777-LMZ779 until 10 AM Friday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO