Flash Flood Guidance
Issued by NWS
Issued by NWS
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
45
46
47
48
49
50
025 AWUS01 KWNH 012211 FFGMPD MSZ000-LAZ000-TXZ000-020410- Mesoscale Precipitation Discussion 0369 NWS Weather Prediction Center College Park MD 611 PM EDT Sat Jun 01 2024 Areas affected...east Texas, much of Louisiana Concerning...Heavy rainfall...Flash flooding possible Valid 012210Z - 020410Z Summary...Flash flood potential continues as a broad axis of slow-moving storms (extending from near Longview to near Alexandria, Baton Rouge, and Slidell) continue to produce locally heavy rainfall (1-3 inch/hr rates). Discussion...Strong thunderstorms continue along a couple of axes/outflow boundaries - 1) drifting slowly northward and extending from near Lufkin to near Alexandria, Baton Rouge, and Slidell and 2) another migrating southeastward across northeast Texas from near Longview to near Palestine. Just ahead of the storms within the pre-convective environment, strong instability (1500-3000 J/kg MLCAPE) and 1.8 inch PW values were sustaining intense updrafts with water loading efficient rain rates approaching 3 inches/hr (especially in south-central Louisiana). Meanwhile, west-northwesterly flow aloft (strongest in Texas and ranging from 30-50 knots) was promoting modest storm organization. Short term trends suggest that the northeast Texas and southern Louisiana outflow boundaries should converge in the general vicinity of Nagodoches, TX to Natchitoches, LA in the next 1-2 hours, resulting in an uptick in convective coverage and flash flood potential from multiple convective mergers. Meanwhile, south-central and south-eastern Louisiana convective will continue to drift slowly northward or perhaps move erratically, with continued areas of 1-3 inch/hr rain rates probable. Eventually, widespread convective overturning should result in a decrease in coverage and intensity through sunset. In the meantime, typical low spots/sensitive areas will continue to experience flash flood potential as storms drift across the region. FFG thresholds are generally in the 2.5 inch/hr range (locally lower), and will occasionally be threatened where slow movement and/or cell mergers are most pronounced. Cook ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...FWD...HGX...JAN...LCH...LIX...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 32799463 32309344 31869242 31359120 30768989 29688922 29058905 29069003 29519156 30409359 30899528 31839599 32669545