Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/28/19


Area Forecast Discussion
National Weather Service Columbia SC
857 PM EDT Thu Jun 27 2019 .SYNOPSIS... High pressure will be centered just to the northeast through Friday. This dry air mass is forecast to persist and help keep thunderstorm coverage isolated on Friday. Some increase in moisture in a southerly flow on the backside of dominate high pressure farther off the Southeast Coast may promote a more seasonally typical scattering of afternoon and evening thunderstorms over the weekend and early next week. && .NEAR TERM /UNTIL 7 AM FRIDAY MORNING/... Moisture convergence and axis of instability across southern NC into the Upstate of SC. Showers and storms in this area affecting the northern tip of Lancaster county for the next hour or so. HRRR model indicating isolating convection across the northern Midlands through the evening...then dry overnight. Time sections show some low level moisture with PWAT values 1.4 to 1.5 inches along with some high level moisture. Not expecting significant fog with weak low level jet near the surface and slightly stronger jet around 4k feet. Temperatures have been consistent over the past couple of mornings with lows in the middle 60s to lower 70s across the Midlands and CSRA. With no real change in airmass will continue with persistence forecast for overnight temperatures. && .SHORT TERM /7 AM FRIDAY MORNING THROUGH SUNDAY/... General surface high pressure is forecast to remain in the region with thermal troughing in the forecast area. The models show this troughing more pronounced Sunday ahead of a cold front. The front should dissipate before reaching the forecast area. Upper ridging may be weaker Sunday with upper troughing mainly affecting the Northeast States brushing the forecast area. Still, moisture should remain limited with h85 westerly flow locally. Projected precipitable water values will be a tad below climatological normals and forecast soundings indicate high LFC values. The NAM, GFS, and ECMWF MOS have pops less than 20 percent. Believe thunderstorms mainly associated with strong heating will be isolated. Leaned toward the lower high temperature guidance based on the recent bias. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... The GFS and ECMWF have surface ridging extending from the Atlantic into the Gulf of Mexico. North of the ridge the models show troughing in the forecast area. Forecast upper ridging should keep this moisture shallow. The ridging will also help bring hot temperatures. The GFS and ECMWF MOS have above normal temperatures and pops 20 percent or less. Peak heat index values may be near 105. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Overnight, there will be periods of high clouds moving from southwest to northeast on modest upper level flow, but low clouds should be gone after sunset. Despite light winds all night, 5K foot winds in excess of 20 knots and a drier than normal air mass will prevent morning fog at terminals, with the exception of OGB where there was some rain nearby this afternoon. Even there, though, it should not cause much in the way of aviation problems. With deep layer ridging in place Friday, VFR conditions and seasonably light winds will prevail. .EXTENDED AVIATION OUTLOOK... A more typical summer time pattern will set up across the Midlands and CSRA through the extended period. As PW values gradually increase over the weekend into early next week, expect isolated to scattered mainly afternoon and evening thunderstorms. This will produce associated restrictions possible Friday through Tuesday. A few locations may have early morning stratus and fog. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Caribou ME
1023 PM EDT Thu Jun 27 2019 .SYNOPSIS... A Low pressure over Hudson Bay will cross the area by Sunday and will be followed by high pressure Monday. Another weather system will affect the region on Tuesday. && .NEAR TERM /THROUGH FRIDAY/... 10:25 PM Update...Both water vapor imagery and latest model guidance are showing a well defined shortwave sliding into the northern part of the area from Quebec. Thunderstorms supported by cooling aloft and divergence aloft ahead of this shortwave continue to affect the northern region and will likely persist well into the evening, weakening around midnight. Forecast was updated to increase thunderstorm coverage from isolated to scattered into late this evening over the north. Temps were lowered a couple degrees where rain has cooled the air a bit. Also, a dense fog advisory was issued for the coastal zones where humid air moving of the colder waters will produce some dense fog overnight. Tstms will be ongoing into the evening mainly across the w and nw areas where the best effective shear(30 kts) and CAPE of 1500 joules reside. As the cells move east, they will weaken running into a more stable airmass. Storms will have the capability of large hail and very heavy rainfall leading to some ponding of water. Damaging winds are also a threat into the early evening. Activity will wind down for a while as the best forcing pushes east w/the pre-frontal boundary and upper trof. The HRRR was doing ok with the movement along w/the RAP and NAM12. Expecting another round of action, not as strong, to move across the northern 1/2 of the region w/the associated cold front overnight into early Friday morning. Could see some heavy rainfall w/this action. Decided to add the mention of heavy rainfall to cover this. Light winds, surface cooling, and partial clearing should lead to fog development overnight. On Friday, fog and low clouds leftover showers to the east in the morning. Expecting some showers and tstms to develop during the afternoon across the northern areas as a mid level trof slides across the region. Instability increases during the afternoon w/tstms setting up. NAM/GFS soundings indicate v-notch sounding w/some shear and CAPE potential of 700-1000 joules. The NAM is most prominent showing decent moisture through 750 mbs. PWATS of 1.2 inches w/K index in the low 30s to allow for storms to keep going. Cell characteristic will be pulse type with hail possible. Giving the shear not expected to be that strong, thinking is wind is not a big threat. Given the higher PWATS and weak steering flow forecast, heavy rainfall also possible. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... At the start of the period, a weak ridge of higher pressure between troughs bring a brief relief from the unsettle weather. By early Saturday morning another trough will move into northern Maine bringing a return of the shower activity across the Crown of Maine. By early afternoon the shower activity will spread across the CWA, showers and thunderstorms will persist through the afternoon. By Saturday evening the TSTMs will move east into New Brunswick. Shower activity will diminish, but will remain in the area through the end of the period. The models they were in good agreement overall through the short term of the forecast period. Loaded a blend of the GFS/NAM/ECMWF/GEM to smooth out the minor differences in the models. && .LONG TERM /MONDAY THROUGH THURSDAY/... Unstable conditions continue through the extended period of the forecast. An upper level low over northern Quebec will continue to spin off troughs through the period. A trough will be over the area at the start of the period. By early Monday morning the trough will move into the Gulf of Maine, Higher pressure will ridge through the area on Monday. Partly to Mostly sunny conditions will become cloudy Monday evening as the next trough moves into NW Maine by early Tuesday morning. This trough will move through Tuesday evening, higher pressure will move in and will remain until overnight Wednesday. Another trough early Thursday morning through early Friday morning. A weak ridge of higher pressure will build in at the end of the period Friday morning Loaded a blend to smooth out the differences in the models. Used NAWAVE4 for seas in the coastal waters. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR this evening dropping down to IFR tonight across all the terminals w/the potential for LIFR. Conditions are expected to improve to MVFR Friday morning and then VFR by afternoon. The exception will be across the northern terminals. SHORT TERM: Generally Low MVFR to IFR conditions through the period with unsettle weather conditions. Periods of IFR during showers and thunderstorms, then conditions will return to Low MVFR. Brief periods of MVFR to VFR conditions between troughs, Sunday evening through Monday afternoon and Tuesday evening to early Wednesday morning. && .MARINE... NEAR TERM: Light sse winds tonight will become sw on Friday w/a slight increase to 10 kts during the day. Seas will hold at 3-4 ft especially across the outer zones. SHORT TERM: Winds and seas below Small Craft Advisory levels through the period. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Dense Fog Advisory until 8 AM EDT Friday for MEZ029-030. MARINE...None. && $$ Near Term...Hewitt/Bloomer Short Term...Norton Long Term...Norton Aviation...Hewitt/Norton Marine...Hewitt/Norton
Area Forecast Discussion
National Weather Service Indianapolis IN
1153 PM EDT Thu Jun 27 2019 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 234 PM EDT Thu Jun 27 2019 High pressure in place across the southeastern states will provide warm and humid summer weather for Central Indiana over the next several days. Chances for very isolated showers or storms will continue to persist each afternoon...but most areas will remain dry...warm and humid through the weekend. The next best chance for more organized precipitation will be on Tuesday and Wednesday as upper level weather disturbances will track into the region as the ridge aloft flattens. && .NEAR TERM /Tonight/... Issued at 234 PM EDT Thu Jun 27 2019 Surface analysis early this afternoon shows a large area of high pressure stretching from the middle Atlantic states...across Kentucky and Tennessee to TX and Louisiana. A warm and humid air mass was in place across the area with dew points in the mid to upper 60s. GOES16 shows mostly clear skies across the state...with a few CU and CI in the area. An MCV was still spinning near the land between the lakes. Aloft a ridge axis was in place from New Mexico to Illinois and Indiana. Storms over the upper midwest were riding the ridge and pushing toward the Great Lakes. Models suggest little change in the weather pattern tonight or through the next several days. The surface high and strong ridging are expected to remain in place. HRRR suggests an isolated shower or storm will be possible due to diurnal heating...but coverage may be too low to be worthy of a mention. Time heights through tonight show only lower level moisture in place along with subsidence. Thus will trend toward a partly cloudy sky along with lows close to persistence values. && .SHORT TERM /Friday through Sunday/... Issued at 234 PM EDT Thu Jun 27 2019 Little change is expected over the next several days in the weather. The GFS and NAM are consistent in keeping the strong area of high pressure in place across the southeastern States. Meanwhile the upper ridge also appears to strengthen. This steers any upper level support well north of Indiana to Ontario and the Great Lakes. Thus over the next several days the only forcing factor will be the diurnal heating of the day to perhaps trigger afternoon showers and storms. Time heights through Saturday morning suggest a dry column and broad subsidence as the strong ridge builds across the area. Furthermore by Saturday and Sunday forecast soundings suggest 700mb temps rise to or above 10C. Thus stronger capping develops as the weekend progresses. Therefore much of the area should remain dry over the next several days...particularly on Saturday and Sunday. A renegade shower or storm cannot be ruled out due to the warm and humid air mass in place...but widespread organized precipitation is not expected. Thus will trend toward the lowest possible pops provided by the NBM during each afternoon. Given the little change in the airmass through the period will trend temps toward persistence. && .LONG TERM /Sunday night through Thursday/... Issued at 306 PM EDT Thu Jun 27 2019 As the long term begins, the upper pattern has upper ridging over central Indiana with very warm temperatures aloft. Generally accepted the initialization throughout. The upper ridging will keep mostly hot and humid conditions over the area with little to no precipitation through Monday. By Monday night, though, the ridging becomes a bit depressed and flow becomes more progressive, which will bring with it more chances for off and on showers and thunderstorms. There are disagreements in the models on the progression of the upper pattern, but think the initialization`s handling of this with some low end shower and storm chances along with temperatures cooling a few degrees (still mid 80s for highs) by the end of the long term seems reasonable. && .AVIATION /Discussion for the 28/06Z TAF Issuance/... Issued at 1149 PM EDT Thu Jun 27 2019 VFR conditions are expected for the duration of the TAF period. However, will not completely rule out some MVFR fog late tonight, will have to continue to monitor though. Meanwhile, winds will generally be light and variable. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM....CP AVIATION...TDUD
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1100 PM CDT Thu Jun 27 2019 .UPDATE... Issued at 910 PM CDT Thu Jun 27 2019 Instability was very sluggish in returning today in the wake of the MCS that came through earlier in the day. However, as we got after 8pm, visible satellite showed a field of accas develop within the WAA associated with the LLJ. RAP MUCAPE analysis shows this LLJ is now bringing some instability up from IA, with thunderstorms developing south of the Twin Cities in response to all of this. Expect this activity to slowly sag southeast through the night with the LLJ. Storms will be elevated and should remain mostly sub-severe, but with MUCAPE in excess of 2000 j/kg and around 40 kts of effective bulk shear, this activity can not be completely ignored for a marginal severe hail threat. && .SHORT TERM...(This evening through Friday night) Issued at 245 PM CDT Thu Jun 27 2019 The primary concern in the short term is the possibility of convective redevelopment later today and this evening. Latest radar imagery shows this morning`s activity has finally exited the area, with just some trailing stratiform precipitation remaining. The MCV resulting from the morning MCS is working its way northeast toward western Lake Superior at the current time, and won`t have any additional impact on our area, except for the subsidence on its backside which is helping to clear out the cloud cover across the western and central portion of the area per the latest visible imagery. HRRR and HopWRF runs still point toward some redevelopment of convection later today near the instability gradient once it re- establishes itself. There remains some question on where and when that will occur, but the current consensus is it would be late afternoon or early evening near or north of I-94. Any storms that develop should move east and southeast, with the best chance to see anything being east of I-35. We`ll need to see how well the instability recovers across the area, but there is at least some chance for a few severe storms. The upper ridge will continue to build into the area Friday and Friday night, with any weak shortwave energy tracking by to our north. So, once we get rid of any precipitation tonight it looks like things will be dry Friday and Friday night with very warm temperatures. .LONG TERM...(Saturday through Thursday) Issued at 250 PM CDT Thu Jun 27 2019 Both the EC/GFS have similar model outputs with the mean long wave pattern through early next week. Thus, the upper ridge that was forecast to build across the Upper Midwest on Saturday, remains on track to produce the hottest air mass since last year. Heat index values, in combination of WBGT depict a higher potential for heat illness for those who are active outdoors Saturday. Depending upon when the cold front arrives on Sunday, southern Minnesota could have another day of these higher values. I wouldn`t be surprised to see a heat advisory issued for parts of Minnesota, and west central Wisconsin on Saturday, and possibly Sunday based on these conditions. The upper ridge will begin to break down late Sunday, especially Monday as a short wave moves rapidly eastward across the Canadian border. Thus, with this short wave, a cold front will arrive. Timing is questionable but likely it will be another hot day with storms Sunday night. Past Sunday night, and due to a persistent fast west to east flow aloft, I can`t rule out any afternoon or evening thunderstorm as Sunday nights frontal boundary will likely be in the vicinity next week. As the front holds close to the area, I don`t see any strong surge of drier air moving southward and this will lead to dew points remaining quite moist. There also remains uncertainty on temperatures next week. I am leaning toward holding on above normal temperatures next week which is more in line with the EC vs. the GFS. This scenario keeps most of the colder Canadian air mass farther north compared to the GFS. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1100 PM CDT Thu Jun 27 2019 Thunderstorms the rest of tonight will remain east and south of MPX terminals, though some activity will be near EAU for the first couple of hours. Still lower than normal confidence on cig trends tonight, but continued to follow the HREF idea with the best chances of reduced cigs/vis being across central MN. We`re already seeing stratus and fog expand across northeast MN and expect this to expand south toward AXN/STC through the night. Low level moisture will slowly mix out through mid morning Friday, with mainly sunny skies with light east winds expected by the afternoon. KMSP...Still lots of spread in the guidance on cig trends for tonight. Did add a tempo group in for lower cigs, but still not convinced we`ll see much develop given where reduced conditions are now. /OUTLOOK FOR KMSP/ Sat...VFR. Winds SE 5-10G15 kts. Sun...VFR. Chc TSRA late. Winds SW 5-10 kts. Mon...VFR. Chc MVFR/TSRA. Winds lgt and vrb. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ UPDATE...MPG SHORT TERM... LONG TERM...JLT AVIATION...MPG