Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/28/17

Area Forecast Discussion
National Weather Service Denver/Boulder CO
825 PM MST Fri Jan 27 2017 .UPDATE... Issued at 817 PM MST Fri Jan 27 2017 Water vapor imagery showing upper trof over far northeast Colorado this evening and moving rapidly south and southeast. This disturbance kicked off some moisture and even a few snow showers on the far plains this evening. However, should see rapid clearing over the plains for the overnight hours. Have adjusted forecast to reflect these latest trends. Other change was to lower temperatures tonight over the high mountain valleys with mainly clear skies. No other changes needed. UPDATE Issued at 554 PM MST Fri Jan 27 2017 Increased winds slightly over the plains overnight following model guidance trends. Current shortwave moving over the northern plains should still only produce cloud cover, though there may be a flurry or two over Phillips or Sedgwick counties according to echoes on radar moving south out of Nebraska. Looking at dew point depressions however would likely result in mainly virga. Added a 10 percent chance of seeing a few snowflakes. && .SHORT TERM...(This evening through Saturday) Issued at 110 PM MST Fri Jan 27 2017 A weak disturbance wl clip the northeast corner of Colorado this evening in the 01-04z windows, with a drier northerly flow for the rest of tonight and Saturday, as an amplified ridge over the west coast. Will keep more cloud cover around this evening with the passing system but no showers expected. The HRRR does show some weak echoes but do not expect this to add up to any pcpn. Lesser cloud coverage thereafter. Main moisture around on Saturday in the 600-400 mb layer. Gusty northerly winds will continue above timberline on Saturday with ridgetop winds in the 35-40 mph range. Adjusted the low temperatures in the mountains and high valleys based off the much colder temperatures this morning. It will not be as cold but some places will still drop to well below zero, -10 to -15F. Across the northeast plains, gusty northwest winds will continue into early evening then taper off. Saturday will remain dry and temperatures will continue to moderate with a little more sunshine. Gusty northwest winds will return to the far northeast plains by the aftn but not as strong as today, with peak gusts around 30 mph. .LONG TERM...(Saturday night through Friday) Issued at 110 PM MST Fri Jan 27 2017 A north-northwest flow aloft will turn more northwesterly Monday and an upper level ridge over the western states flattens and shifts a little east. Gusty winds will be possible over far northeast Colorado Sunday afternoon, otherwise dry and quiet conditions are expected through Monday. Temperatures will climb above normal for Sunday and Monday with readings in the 50s over northeast Colorado. Continued warm and dry conditions are expected for Tuesday and Wednesday with a west-northwest flow aloft overhead. The ridge axis finally shifts across Colorado late Wednesday. High temperatures across northeast Colorado are expected to remain in the 50s. A progressive westerly flow aloft will be over the western CONUS Thursday and Friday. The ECMWF shows a wave embedded in the westerly flow late Friday. Will have low pops for the mountains for this system. A downslope flow will keep areas east of the mountains dry. Temperatures are expected to remain above normal. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 817 PM MST Fri Jan 27 2017 After a brief wind shift to the east and Northeast at KDEN, winds will now shift back east through south through 06z. Skies have cleared out, with a mid level deck of clouds mainly East of KDEN for the next few hours. Some increase in high level clouds expected again Saturday morning from the North. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Entrekin SHORT TERM...Cooper LONG TERM...Meier AVIATION...Entrekin
Area Forecast Discussion
National Weather Service Wilmington OH
925 PM EST Fri Jan 27 2017 .SYNOPSIS... Northwest flow aloft will allow for slightly below normal temperatures into the weekend, with the potential for a few flurries or light snow showers each day. The best threat for snow showers will occur Sunday night as an upper level disturbance moves through the Ohio Valley. High pressure will build into the Ohio Valley providing drier weather by the middle of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... An 850mb shortwave is currently moving through the ILN CWA from west to east, with a weak surface trough also apparent underneath. Though not really evident on satellite imagery, there is a definite min in 850mb theta-e depicted on 18Z NAM / 01Z RAP projections, roughly coincident with the wave. Ahead of the wave, there has been continued weak ascent, leading to flurries and light snow showers. Along the wave, wind gusts are briefly picking up into the 25-30 knot range. Behind the wave, subsidence is leading to a shut-down of any precipitation, and (eventually) a back edge to the stratocumulus, currently entering far western Indiana. PoPs for light snow have been kept in the forecast for another couple hours, but ending from west to east as the overnight period progresses. Sky grids were also changed to allow for some clearing, mainly in the far southwestern CWA. Based on current T/Sky/Wind trends (and the slight increase in cold advection currently occurring) min temps were dropped slightly, mainly in the western half of the CWA. Previous discussion > Mid level shortwave which pivoted through the region, along with steep lapse rates and favorable dendritic growth, led to numerous snow showers today. With this shortwave axis shifting east, expect precipitation to diminish during the late afternoon into early this evening. Numerical models show another weak s/w leading to an enhanced period of snow showers later tonight. Solutions differ on exact timing, but expect best time from about 04Z through 09Z. Low level moisture continues to hold on with skies remaining mostly cloudy. Lows tonight generally in the middle 20s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... In the wake of mid level shortwave, expect a general dry period Saturday with a good deal of clouds lingering. Temperatures will be close to normal, with highs ranging from the lower 30s northwest to the upper 30s southeast. Next mid level shortwave to drop southeast though the Great Lakes Saturday night/Sunday morning and into the Ohio valley Sunday afternoon/Sunday night. Will ramp up snow shower pops with the best chance Sunday afternoon into Sunday evening. Temperatures continue to be at or a little below normal. Lows Saturday night to range from the lower 20s north to the upper 20s south. Highs on Sunday generally upper 20s to lower 30s and lows Sunday night upper teens northwest to middle 20s southeast. && .LONG TERM /MONDAY THROUGH FRIDAY/... Models continue to show a long wave upper trough in place over the eastern CONUS. This pattern will leave the ILN area under a northwest flow aloft, providing little moisture, while main band of forcing remains to the north. A few snow showers may linger in eastern locations Monday behind a departing short wave trough. Otherwise, skies will be mostly cloudy. A chunk of short wave energy will develop a surface low over the Great Lakes on Tuesday. This system will provide a chance for snow showers across the north half of the FA. For Wednesday through Friday, scant moisture and forcing associated with a flattening upper flow over surface high pressure is forecast to keep precip out of the area. Temperatures start out chilly Monday with highs in the lower 30s. A brief round of warm advection Tuesday is expected to boost readings to around 40. Highs are then forecast to retreat back into the 30s for Wednesday through Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... The chance for flurries (and possibly an MVFR snow shower) will continue through the next few hours, before precipitation is likely to come to an end going into the overnight period. While ceilings are currently just above or below the MVFR threshold (around 2500-3500 feet), a gradual drop in ceilings is expected, with prevailing MVFR conditions overnight. The one exception to this will be at KCVG, where a period of some scattering of the clouds is expected late in the overnight and through most of Saturday morning. Ceilings will likely become VFR at all TAF sites during the mid-day on Saturday. However, MVFR ceilings are expected again at all locations by Saturday night. Winds will remain fairly steady through the period - out of the WSW with occasional gusts to around 20 knots. OUTLOOK...MVFR ceilings are likely from Saturday night through Monday, with occasional MVFR/IFR visibilities possible in snow showers. Some MVFR conditions are possible again on Tuesday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...Hatzos/AR SHORT TERM...AR LONG TERM...Coniglio AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Melbourne FL
857 PM EST Fri Jan 27 2017 .UPDATE... ...Below Normal Temperatures Through Early Next Week... ...A Cold Rain will Develop Saturday Night into Sunday... Tonight...At the surface, a high pressure ridge extending along the northern Gulf of Mexico coast will continue to provide a northwest wind flow of cool/dry air. Satellite was showing an extensive area of mid clouds over the Gulf streaming eastward with a more narrow band extending across central Florida. The low temperature forecast hinges on how much clearing out of these clouds occurs. Surface dew points remained quiet low this evening with values in the 30s and 40s but the cloud cover was keeping temperatures several degrees above forecast values in most areas. The HRRR model shows moisture fields will support diminishing cloud cover, especially across the north half. There is low confidence in this since recent satellite trends suggest otherwise. Have raised cloud cover some and only nudged temps up a degree or two, thinking that there will be cloudy periods and a few clear periods, which should allow temperatures to fall into the 40s areawide. ...Previous Discussion... Sat...Cold air advection will produce below normal temperatures with highs ranging from around 60F Lake/Volusia to the upper 60s in Martin county. More sun than clouds in the morning will give way to top-down moistening as mid level moisture increases ahead of an approaching shortwave trough. No rain is expected during the day but skies may become overcast with altocumulus by sunset across the north. Sat Night-Sun Night...Increasing moisture across the area combined with ample shortwave/jet stream energy aloft will promote higher rain chances (prolonged light rainfall event) across ECFL. A cold front will pass through the area Sun night and take precipitation chances with it eastward. It will be a cold rain (for east central Florida) with temps Sat night in the 40s. Sun will be cool and damp, even raw for Florida, with overcast skies and on and off showers especially in the morning. Some drier air should move into northern sections (north of Orlando) during Sunday afternoon but a high overcast should keep skies cloudy. Highs on Sat and lows Sat night/Sun night will average 7-15 degrees below climo areawide. && .AVIATION... VFR through 00Z/29. West to Northwest winds 5 to 10 knots. && .MARINE... Tonight/Sat...A slight tightening of the pressure gradient is indicated late tonight as a ridge builds along the Gulf coast while a broad frontal trough over the Atlantic only moves slowly away. So a northwest wind flow at 15-20 knots should develop in the open Atlantic and continue into Sat morning. A diminishing of winds is forecast Sat afternoon, but exercise caution statements will likely be headlined for the early morning hours offshore north of Sebastian Inlet. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ SHORT TERM...Lascody IMPACT WX....Glitto