Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/23/19

Area Forecast Discussion
National Weather Service Cheyenne WY
814 PM MDT Mon Apr 22 2019 .UPDATE... Issued at 806 PM MDT Mon Apr 22 2019 Dense Fog Advisory has been allowed to expire. A few patches of dense fog remain, especially near the I-80 Summit, however coverage has decreased and should remain localized through tonight. Will continue to monitor webcams in the case dense fog becomes more widespread. UPDATE Issued at 523 PM MDT Mon Apr 22 2019 Webcams near the I-80 Summit still show dense fog in spots with surface easterlies creating upslope flow. Areas of dense fog will continue early this evening before winds begin to turn more southerly. Therefore extended the Dense Fog Advisory through 8 PM MDT. && .SHORT TERM...(Late this afternoon - Tuesday night) Issued at 315 PM MDT Mon Apr 22 2019 The afternoon WV/IR imagery showed a progressive northern stream flow aloft with a slower southern stream marked by a southward drifting mid/upper low over southeast CA/western AZ. Surface analysis showed the remnants of boundary that moved through the CWA yesterday was located from south central WY into western CO. Scattered showers and a few weak tstorms were developing over southern Carbon County and will spread to the north and east through late afternoon. Stubborn low stratus and fog formed this morning over portions of southeast WY. The fog has been dense from the I-80 Summit to Vedauwoo. A Dense Fog Advisory is in effect for these areas until 6 PM, however the HRRR prolongs the fog and low clouds through late tonight. Added fog for the I-80 corridor from Arlington to Cheyenne and Pine Bluffs. The short range models/ensembles are in good agreement with the large scale flow aloft. The southern stream low tracks southeast into northern Mexico, with ridging aloft becoming the dominant feature for the CWA. This pattern will promote milder and drier weather Tuesday and Tuesday night. .LONG TERM...(Wednesday - Monday) Issued at 302 AM MDT Mon Apr 22 2019 A muddled extended forecast period with the models showing broad & flat upper-level ridging evolving across the western/central CONUS during the mid/late week time frame. In general, this should yield warmer temperatures for the most part. However, not necessarily on the dry side as the area is likely to be on the northern fringe of the aforementioned ridge. Quasi-zonal flow aloft prevails along w/ numerous waves embedded within the general flow pattern. A frontal boundary appears to slip into our northern & eastern zones by late Wednesday, possibly supporting shower/thunderstorm chances. Models suggest quite a few additional weak ripples through Saturday. This may support isolated showers somewhere in our CWA on a daily basis through the period. Fortunately, no major storms appear likely for the foreseeable future. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 451 PM MDT Mon Apr 22 2019 Airport of concern this evening is KCYS. We did break the IFR conditions late afternoon that brought them to MVFR. Concern is that the lower conditions could lower back down after sunset. Nothing indicating this happening...but winds are not changing from what we had all day. Even more southeasterly directions would be favorable for lower ceilings. For now...will monitor WYDOT Webcams west of Cheyenne. If they show a lowering of ceilings over time...will likely need to lower to IFR through and amendment. Improving conditions elsewhere. && .FIRE WEATHER... Issued at 302 AM MDT Mon Apr 22 2019 No fire weather concerns w/ much cooler temperatures over the next 24-48 hours with recent precipitation across most districts. Highs will trend warmer from Tuesday onward, but RH values should remain well outside of critical thresholds in the afternoons w/ excellent recoveries overnight. && .HYDROLOGY... Issued at 235 PM MDT Mon Apr 22 2019 Milder temperatures are forecast from Tuesday through Sunday. There will be slight chances of mainly afternoon and evening showers and thunderstorms Wednesday through Monday. Heavy precipitation is not expected. High temperatures above 8500 ft will result in some snow melt runoff, mitigated by freezing low temperatures. There is the possibility of rain on snow from mid-week onward, which will cause rivers and streams to run high for the next several days. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...MB SHORT TERM...MJ LONG TERM...CLH AVIATION...GCC FIRE WEATHER...CLH HYDROLOGY...MAJ
Area Forecast Discussion
National Weather Service Gray ME
1029 PM EDT Mon Apr 22 2019 .SYNOPSIS... Low pressure south of New England will move northward tonight to a position just south of Nova Scotia Tuesday evening. This low will bring the region more rainfall, the heaviest of which will be on the coastal plain. Another low pressure system will approach from the west Tuesday night bringing more rain to the region Tuesday night into Wednesday. More rain is expected by the end of the week with another low pressure system. Temperatures will be colder than normal to near normal through much of the forecast period. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Update...Most notable at this hour is an upper level feature rotating onshore near Cape Ann. Almost like a MCV...this cyclonic swirl is very evident on IR satellite imagery. What it is doing is peeling off a piece of higher PWAT air...near 1 inch...from the main atmospheric river well offshore. This is also occurring in the left exit region of the H5 jet and in a region of 300 mb jet divergence. This is supporting the lift to take advantage of the high PWATs and produce occasionally heavy rainfall in the SErn NH and SWrn ME vicinity. Dual-pol DPR is suggesting rates briefly nearing 2 inches per hour are possible in the heaviest bands. I have increased QPF amounts slightly and expanded the area of heavy rainfall wording in the grids. Hi-res guidance is highlighting the Seacoast region as most likely to see heavy excess of 1 inch overnight. HREF probability matched mean QPF is showing around 1.5 with locally higher amounts approaching 2 inches for this region as well. This is the same region the HRRR and HRRRE is highlighting as well. So I feel comfortable with heavy rain wording there. 1 hr QPF forecasts also show the window from roughly now through 2 AM to be most likely window for heavy rainfall. Hourly rates pushing a half inch could lead to some standing water on roadways and urban/small stream type flooding given the wet ground primed for runoff. Previous discussion...Stacked low pressure south of New England this Monday afternoon will slowly move northeastward to a position in the Gulf of Maine Tuesday. Rain is already spreading northward into southern NH as of this writing and will continue to spread northward this evening. A period of moderate midlevel frontogenesis this evening and overnight will move northward over the coastal plain aiding in moderate to locally heavy periods of rain. While the main plume of high PWATS will be located offshore, CCB will contain PWATS over an inch over portion of Maine and New Hampshire, possibly aiding in total rainfall amounts between 1-1.5" in spots. The heaviest rainfall is expected on the coastal plain, with the Seacoast of NH and York County ME the best candidates to see those higher amounts. At this time, we are expecting the heaviest QPF axis to stay south and east of the mountains so any river rises should not be overly troublesome. Will continue to watch trends, however. In any case, urban and small stream flooding will be a possibility overnight on the coastal plain. Thunder not out of the question on the immediate coast tonight, but probabilities too low at this time to include in forecast. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Low pressure will continue to move northeastward through the Gulf of Maine on Tuesday, with the rain moving out of southern New Hampshire late tonight or early Tuesday morning, and most of our Maine zones by midday. However, a quick-moving short wave trough will approach from the west late in the day bringing more showers to the region Tuesday night. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Upper level low moving through the Great Lakes will generate some residual showers Wednesday morning. Upslope conditions in the mountains will keep showery precipitation in place longer there. Upper level flow turns more westerly behind the system on Thursday. This will allow temperatures to warm a little bit from Wednesday and should result in a dry day as well... probably the nicest day of the work week. Low pressure begins to develop over the mid Atlantic states Friday morning, with precipitation moving into the forecast area by midday. The system turns into a bit of a coastal low as it deepens over the Gulf of Maine. Precipitation Friday afternoon and evening could be fairly heavy in places. This system pulls off into the Canadian maritimes rather quickly, with northwest flow returning for Saturday. It looks like there will probably be a decent pressure gradient behind the system on Saturday, so would expect gusty winds. The dry weather on Saturday will be short lived as another low pressure system moving through the Great Lakes will approach the region Saturday night. This looks like a very fast moving system and will likely produce at least some precipitation. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... Short Term...MVFR to higher-end IFR expected for most terminals tonight in low clouds and rain. However, LIFR conditions will be possible on the immediate coast. Some improvement is foreseen for Tuesday, especially midday onward. However, lower conditions will re-enter the picture Tuesday night with more rain. Long Term...Expect VFR conditions on Wednesday and Thursday, deteriorating to IFR/LIFR conditions on Friday as a coastal low generates some widespread rain. && .MARINE... Short Term...Northeasterly SCA-level winds are expected on the ocean waters tonight through Tuesday as low pressure gradually passes off to our east. Seas will build accordingly as well. Long Term...May need an SCA for winds on Wednesday in the wake of low pressure moving through the area. A stronger system will affect the waters on Friday, with SCA criteria being met or possibly even reaching Gales. && .HYDROLOGY... Rivers will remain high through the week with additional snowmelt and several chances for rain. We will have to monitor this situation closely, as it would not take too much rain to cause the rivers to rise again, especially tonight and Tuesday. At this time, highest rainfall amounts are likely to be on the coastal plain tonight. However, up to a half inch will be possible in some basins in the foothills which could result in some modest additional rises. On the coastal plain, some small stream, urban and poor drainage flooding will be possible. Will also have to watch for a potentially significant rainfall Fri- Sat as some deterministic guidance and ensemble members suggest. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ150-152-154. && $$ NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Marquette MI
636 PM EDT Mon Apr 22 2019 .SHORT TERM...(This evening through Tuesday) Issued at 428 PM EDT MON APR 22 2019 WV imagery and RAP analysis indicated a mid/upper level trough from southern Manitoba through the upper Mississippi Valley. A prominent shortwave trough over northeast IA was lifting slowly to the northeast. At the surface, low pressure was located over northeast IA with a warm front to the northeast through central WI. Strong 800-600 mb fgen and associated upper level div with the right entrance of the 250-300 mb jet through nrn Ontario supported an area of light to moderate rain from western WI into wrn Upper Michigan. Late this afternoon into tonight, although the stronger fgen over the west is expected to lift off to the northeast and weaken this evening, increasing 700-300 qvector conv ahead of the shrtwv should still maintain the area of rain as it slides to the east through Upper Michigan. Upslope northeast flow into north central Upper Michigan should also help to boost rainfall amounts. With additional QPF in the 0.35-0.75 inch range along with continued snowmelt runoff, the Flood Watch and ESF highlighting lingering flood risks were maintained. Locally dense fog in upslope flow locations north should also diminish as the rain moves in this evening and drier air with greater mixing takes over late. Tuesday, mid level and sfc ridging will move in with clouds clearing from west to east in the morning but may linger a bit longer north central where upslope flow continues. Even with afternoon sunshine, northerly winds will keep highs in the 40s north while reading climb into the lower to mid 50s south. .LONG TERM...(Tuesday night through Monday) Issued at 310 PM EDT MON APR 22 2019 An active pattern through the middle/end of this week and through the weekend will bring additional chance for precipitation, especially this weekend. It isn`t out of the question that we could see snow return to the Upper Peninsula this weekend; however, this is highly dependent on how the system evolves as it tracks across the region and how much cold air is drawn into the system. Ahead of the first shortwave expected towards the middle of the week, Wednesday morning will be rather chilly but temperatures should rebound nicely into the 60s during the day. Shortwave energy will track along the US/Canadian border gradually pushing a weak cold front across the Upper Peninsula late Wednesday/Wednesday night. Ahead of the front, warm and breezy conditions will push us back towards elevated fire weather conditions. However, the combination of recent rainfall and moisture/return flow bumping RHs up into the 30-40% range, we may not quite reach the elevated threshold. Wednesday afternoon could see some rain shower activity with warm air advection, but not really impressive with precipitation chances until the main front arrives and moisture transport increases along and ahead of the front Wednesday night into Thursday. As the front clears the south central and far eastern parts of Upper Michigan Thursday afternoon, a few models are hinting at some elevated instability. Wasn`t enough to put thunder in the forecast, but certainly not out of the question to hear a few rumbles of Thunder across the south central on Thursday. Elsewhere, during the day on Thursday conditions will dry out. For the end of the work week, we will cool down and dry out. However, a stronger storm quickly developing in the lee of the Rockies and tracking towards the Great Lakes region will bring return chances for precipitation Saturday into Sunday. While the system will be quick-moving, the GFS/Canadian hint towards rapid- intensification as it tracks towards and across the Upper Peninsula due to a much stronger shortwave aloft compared to the ECMWF. The stronger model solutions usher in much more widespread precipitation and better chance for light snow Saturday night/Sunday morning. Will be interesting to see how the models continue to trend with this system over the up and coming days. Certainly a time period work keeping a close eye on. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 635 PM EDT MON APR 22 2019 IFR/LIFR conditions will persist at all sites under occasional rain into this evening. Although northeast winds are not as favorable for lower conditions at CMX, expect cigs to lower with more persistent rain. Conditions shoud improve to MVFR at IWD and CMX late tonight and at SAW Tuesday morning and quickly to VFR first at IWD and last at SAW tue morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 428 PM EDT MON APR 22 2019 Northeast winds of 15 to 25 knots are expected on the western end of Lake Superior this evening with north winds 20 to 25 knots into central Lake Superior tonight and to 30 knots over the east half late tonight into Tuesday as low pressure lifts northeast from IA toward Quebec. Otherwise, a quiet stretch of weather will continue from midweek on as winds remain below at or below 20 knots. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Flood Watch through Tuesday afternoon for MIZ001>005-009-010-084. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Ritzman AVIATION...07 MARINE...JLB