Area Forecast Discussion
Issued by NWS Lake Charles, LA
Issued by NWS Lake Charles, LA
Versions:
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
522 FXUS64 KLCH 181652 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1152 AM CDT Tue Jun 18 2024 ...New UPDATE... .UPDATE... Issued at 1136 AM CDT Tue Jun 18 2024 PTC 1 consists of a very broad area of rotation in the southwest Gulf of Mexico. A should of light rain is beginning to move into the area from this disturbance. A few isolated thunderstorms may develop within the mix but ultimately there is a low risk of severe weather. However an isolated gust or brief, weak tornado could be possible. 11/Calhoun && .SYNOPSIS... Issued at 454 AM CDT Tue Jun 18 2024 Latest IR and WV imagery shows Potential Tropical Cyclone 1 situated over the Bay of Campeche, with a broad plume of tropical moisture streaming north across the Gulf of Mexico into LA early this morning. This was producing a swath of light to moderate rain over eastern portions of the CWA and the adjacent coastal waters, with an occasional lightning strike in a few embedded stronger cells over the waters per KLCH radar. Radar estimated rainfall amounts over the past couple of days shows an area of 2-4 inches across portions of southern LA along with some isolated amounts to around 5 inches, while most areas have had less than an inch elsewhere. The latest guidance from NHC keeps the system in the southwestern Gulf of Mexico the next few days, eventually moving west northwest to west toward the northeast coast of Mexico by late Wednesday into early Thursday. While the system will remain well south of our area, impacts will still be felt primarily over our coastal waters with strong and gusty easterly winds, large and very rough wave and flooding in coastal areas of SE TX and SW LA. Abnormally high moisture content in the atmosphere (with PWATs exceeding 2.2 inches) will also contribute to the potential for very heavy rainfall in some of the showers or storms, mainly across our lower SE TX and SW LA zones. Conditions will remain unsettled at least through Wednesday, but should begin to improve some by Thursday. However, coastal flooding may persist into the latter part of the week as water levels will be slow to recover as easterly winds gradually diminish. 24 && .SHORT TERM... (Today through Thursday night) Issued at 454 AM CDT Tue Jun 18 2024 Deep southeasterly flow between an elongated midlevel trough over the western Gulf associated with PTC 1 and ridging over the mid- Atlantic coast will continue to tap deep tropical moisture from the southern Gulf and western Caribbean. The latest LAPS Precipitable Water analysis shows PWATs near 2.1 inches, and these values are expected to surge to between 2.2 and 2.5 inches across our SW zones later today into tonight. Broad ascent within the very moist and uncapped atmosphere will facilitate development of widespread showers across the region again today, Given the unusually high moisture content, precipitation efficiency will be maximized resulting in the potential for torrential downpours with rainfall rates of up to 3 inches an hour. Needless to say, this would be problematic in any urban areas, and a Flood Watch remains in effect for portions of lower SE TX. The good news is that guidance continues to show most of the heavier rainfall consolidating further to the southwest, and this is reflected in the latest ERO for today with the Moderate Risk (level 3 out of 4) now confined mainly to Jefferson County, with the Slight Risk (level 2 out of 4) from Hardin County southeast toward Vermilion Parish. The northern sections (roughly north of Highway 190) are no longer outlined in any excessive rainfall risk. The risk for coastal flooding has remained consistent over the past couple of days. P-ETSS guidance continues to indicate tide levels between 2 and 3 FT MHHW at Texas Point and between 1.5 and 2.5 FT MHHW at Calcasieu Pass at times of high tide between late tonight into Wednesday morning. Guidance spread has narrowed some, with the boundary of the 10th and 90th percentiles within flood warning criteria. The Coastal Flood Warning for Jefferson County and Cameron Parish remains in effect, and has been extended through 12Z Thursday as another high tide could reach 2.0 FT MHHW again. A Coastal Flood Advisory remains in effect for southern Calcasieu Parish and southern Orange County around Sabine and Calcasieu Lakes, as well as further east across lower Vermilion, Iberia, and St. Mary Parishes. By Wednesday, the bulk of the moisture and energy associated with the system will shift westward into TX, with slightly drier air beginning to filter into the region as the ridge over the east coast builds west. The weather pattern will begin transitioning on Wednesday and Thursday toward a more seasonal one with mainly scattered daytime convection forming along the seabreeze and other mesoscale boundaries. Daytime temperatures will be cooler than normal thanks to widespread clouds and showers today, and highs could struggle to reach the middle 80s. As rain chances begin to diminish over the next few days, highs will warm back to around 90 or into the lower 90s each afternoon. 24 && .LONG TERM... (Friday through Tuesday) Issued at 454 AM CDT Tue Jun 18 2024 Large mid to upper level ridge of high pressure over the Gulf and Southeastern U.S. states expected to be the dominate weather feature Friday through Sunday. Lingering moisture across the Gulf expected to keep chances of showers and thunderstorms across the coastal waters, diminishing chances further inland as the ridge provides additional subsidence. Afternoon temperatures in the lower 90s expected Friday. With the ridge of high pressure nearly overhead Saturday and Sunday, afternoon temperatures expected to increase in the mid to upper 90s north of I-10, lower to mid 90s further south. Lows in the lower to mid 70s. Heat index values expected to rise as well, likely in the 102-107 range, possibly approaching Heat Advisory criteria (heat index of 108-112 for our region). Monday and Tuesday, the mid to upper level ridge weakens as a broad mid to upper level trough prevails over the Central U.S. The trough should allow moisture from another tropical disturbance across the Southwest Gulf of Mexico to advanced further northward, increasing chances for showers and thunderstorms further inland. Blended guidance shows 40-60% for Monday and Tuesday, mainly during the afternoons. Highs in the lower to mid 90s north of I-10, and upper 80s to lower 90s closer to the coast. 08/DML && .AVIATION... (12Z TAFS) Issued at 650 AM CDT Tue Jun 18 2024 TAF sites this morning are VFR (BKN between 10K and 12K FT) although some SCT low clouds are noted around the area, with a few obs sites reporting IFR cigs. Expect generally VFR conditions with cigs between 3500-6000 FT today amid increasing SHRA and isolated TSRA. Convection should become more widespread at the southern terminals through the morning, with periods of MVFR or lower vsbys/cigs. A few wind gusts to 30-35 KT will also be possible within some of the activity. Outside of convection, easterly winds around 10 KT are expected at AEX/ARA/LFT, while speeds will be sustained 12-18 KT with gusts up to 25 KT at BPT/LCH. Convection should begin to diminish from east to west late tonight, with MVFR cigs possible at BPT/LCH overnight. 24 && .MARINE... Issued at 454 AM CDT Tue Jun 18 2024 Potential Tropical Cyclone 1 will gradually move west northwest across the southwestern Gulf of Mexico toward the northeast coast of Mexico by Wednesday night. A rather large wind field associated with the system, along with a tight gradient across the northwest Gulf of Mexico, will provide moderate to strong and gusty east to southeast winds in the 20 to 30 knot sustained range with occasional gusts up to 40 knots. This will also allow for wave heights to increase in the 7 to 14 foot range. A Small Craft Advisory will be in effect through mid week. As long as the system stays weak, deep moisture will be out from the north side of the system, keeping widespread showers and storms through mid week. 24/Rua && .PRELIMINARY POINT TEMPS/POPS... AEX 85 72 89 72 / 40 40 30 0 LCH 84 75 89 76 / 70 70 70 30 LFT 84 76 91 77 / 70 50 60 10 BPT 86 75 88 77 / 70 70 80 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Coastal Flood Warning until 7 AM CDT Thursday for LAZ073-074. Coastal Flood Advisory until 7 AM CDT Thursday for LAZ241- 252>254. TX...Coastal Flood Warning until 7 AM CDT Thursday for TXZ615. Coastal Flood Advisory until 7 AM CDT Thursday for TXZ616. Flood Watch through Wednesday evening for TXZ201-515-516-615-616. GM...Small Craft Advisory until 7 AM CDT Thursday for GMZ450-452-455- 470-472-475. && $$ SHORT TERM...24 LONG TERM....08 AVIATION...11