Area Forecast Discussion
Issued by NWS Houston/Galveston, TXVersions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
527 FXUS64 KHGX 052327 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 627 PM CDT Mon Apr 5 2021 .AVIATION [00Z TAF Issuance]... Continued southerly winds have enhanced moisture transport to SE TX, and the resultant increases in low-level saturation are likely to bring some restricted cigs to area terminals overnight. In general, this can be expected around 09Z, persisting until sunrise tomorrow morning. Forecast soundings indicate the prevailing deck dropping to around 1 to 2 kft, though have included a FEW group at IFR levels in some sites to account for the more aggressive scenario presented by the NAM. Elevated winds in response to the tightening surface pressure gradient will likely inhibit fog development overnight. However, have included MIFG and some reduced visibilities in northern/metro terminals where stable boundary layer winds are expected to diminish the most. Tomorrow, expect cigs to lift with gusty south winds developing in the afternoon (around 15 kts gusting to around 25kts). Cady && .PREV DISCUSSION... /ISSUED 329 PM CDT Mon Apr 5 2021/ SHORT TERM [Today Through Tuesday Night]... Much of the same weather pattern setup from these last two days occurred today with rainfall having a hard time reaching the surface due to much drier air in place just below it. Accumulations so far have been minimal. For tonight, expect southerly wind flow at around 10-16 MPH with lows generally in the low to mid 60s areawide. Low ceilings are expected to return tonight into Tuesday morning with the potential for some areas of fog, mostly shallow. The NAM forecast soundings and SREF model hint at a more aggressive fog development, but the winds may keep it from thickening that much or could at least keep it above the Dense Fog Advisory threshold. However, it`s fog we are talking about, and many times it acts differently from what is expected. For the time being, have added an area with patchy fog in the Wx grids from 09-14Z. Tuesday, any fog that does develop is expected to burn off an hour or two after sunrise. Ceilings will also lift during the morning hours and scatter out during the afternoon hours. Breezy conditions expected as the local pressure gradient tightens in response to a strengthening low pressure system over the Great Plains while high pressure stays situated over SE CONUS. Southerly winds will range between 12-18 MPH during the day with higher gusts on occasion. Other than the aforementioned items, the overall weather conditions will be relatively warm and tranquil: high temperatures reaching the low 80s (mid to upper 70s along the coasts) with a slight chance of rain mostly along the northern and central portions of SE Texas. Another mostly cloudy night expected Tuesday night with lows in the mid to upper 60s areawide. 24 LONG TERM [Wednesday Through Monday]... Wednesday will feature quite an interesting setup with an upper- level low attempting to drag a cold front through the area in the afternoon hours. Models are in fairly good agreement on the front grazing our far northern counties before stalling and retreating back to the north. The front will be able to trigger scattered showers and thunderstorms mainly in our northeastern counties. Most of the CWA will have a strong capping inversion around 850mb in place that will inhibit thunderstorm development. An incoming jet streak on the western flank of an upper-level trough will place the region under the right exit region which means upper-level convergence, so thunderstorm development even in our northeastern counties will lean likely closer towards isolated coverage. SPC has our far eastern counties outlined in a marginal risk for strong to severe storms for Wednesday afternoon/evening. PoPs diminish for Thursday before increasing again on Friday afternoon. Before we discuss that, let`s talk temperatures since that`s the hot topic of the week (pun intended). Due to the weak cold front grazing our northeastern counties, some slight reprieve is expected with high temperatures for Wednesday in the upper 70s/low 80s for this region. Elsewhere, expect more of the same with low-to-mid 80s for highs. It doesn`t stop there as afternoon temperatures approach the 90s on Thursday and Friday with highs in the upper 80s for most of SE Texas. Now let`s talk about Friday. An upper-level low swinging down from the Central Plains will push a cold front into north Texas on Friday. Models are in agreement on low pressure developing on the tail-end of this front in central Texas. There are a few features that makes this setup more favorable for thunderstorm development when compared to Wednesday: a weaker capping inversion, LI values -11 to -8, CAPE greater than 3000 J/kg, and upper-level divergence in the left exit region of a jet streak. All-in-all, expecting a much better chance for thunderstorms on Friday afternoon/evening across the area as the low slides eastward across the area. Winds become briefly northeasterly Friday night through Saturday afternoon, so highs for Saturday will be a tiny bit "cooler" in the mid 80s. The temperature trend going into next week is an upward one with highs in the mid-to-upper 80s for Sunday and Monday as an upper- level ridge begins to develop over the central CONUS. Batiste MARINE... Southerly to southeasterly onshore flow will prevail through the rest of the work week. A tightening pressure gradient in response to developing low pressure in the Central Plains will increase winds to at least caution levels for Tuesday and Wednesday. Seas will rise as well with offshore wave heights reaching 6-7 feet by Wednesday before subsiding going into Thursday. Dew points will also steadily increase throughout the week and with nearshore water temperatures still in the mid 60s, there is the potential for patchy sea fog to develop starting on Tuesday night. Not expecting the sea fog to be dense since persistent warm air advection will increase water temperatures throughout the week. Batiste && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 62 83 66 83 60 / 10 10 10 30 10 Houston (IAH) 64 82 67 82 64 / 10 20 10 30 20 Galveston (GLS) 67 76 69 76 67 / 10 10 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
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