Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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
824 FXUS64 KMEG 261720 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1220 PM CDT Thu Sep 26 2024 ...New AVIATION... .UPDATE... Issued at 1044 AM CDT Thu Sep 26 2024 Helene is currently accelerating north in the Gulf of Mexico and will make landfall this evening in the Apalachee Bay as a major hurricane. Impacts are expected to extend into W TN starting tonight. The biggest change in the forecast is an increase in winds within the HREF and NBM. Although we have to look at 75th percentile and up, there is a large enough signal for winds in excess of 25 mph to warrant a wind advisory for Friday to around midnight Saturday throughout the MS River delta and our northern tier of counties. Additionally, a persistent signal for wind gusts exists at or above 40 mph across much of the aforementioned region. In summary, expect a wind advisory to be issued for Friday with the afternoon forecast package. JAB && .SYNOPSIS... Issued at 317 AM CDT Thu Sep 26 2024 Showers from Helene will begin across the Mid-South tonight. A Flood Watch will go into effect tonight at 7 PM and persist until 7 AM Saturday morning for West Tennessee, the Missouri Bootheel, most of eastern Arkansas, and a portion of north Mississippi. Rain chances will begin to decrease Saturday and slowly phase out by Monday. Dry and cool conditions return Tuesday. && .DISCUSSION... (Today through Wednesday) Issued at 317 AM CDT Thu Sep 26 2024 A low pressure system is currently parked along the KY/IN/IL borders at this hour. Hurricane Helene will make landfall this evening along the Panhandle of Florida. The large and quick moving system will then track northwest towards the Mid-South. Due to the size of the system, outer rain bands will begin to approach the area around sunset tonight. A Flood Watch will go into effect tonight at 7 PM and persist until 7 AM Saturday morning for West Tennessee, the Missouri Bootheel, most of eastern Arkansas, and a portion of north Mississippi. For these areas, generally 3-4" of rain is expected between tonight and Saturday morning. The bulk of this rainfall will occur on Friday. Guidance has been trending to show an axis of heavy rainfall from Blytheville, Arkansas to Martin, Tennessee with 4-6" expected. This axis of heavy rainfall could shift, so monitor the forecast closely. The short lived tropical rain is due to Helene`s interaction with the cutoff low. A Fujiwara effect seems likely with these two systems, which will bring some additional gusty winds across West Tennessee, the Missouri Bootheel, and northeast Arkansas. There is roughly a 40-60% chance of wind gusts 40 mph or higher on Friday for Memphis and northward. Helene will eventually phase with the upper low and lift towards the Ohio Valley and leave light to moderate showers on Saturday. A few light/drizzle showers are possible on Sunday as the system pulls away from the region. A pattern change will arrive Monday evening as a dry cold front approaches from the northwest. This front will quickly cross the region and allow high pressure to settle in. Dry and cool conditions will prevail from Tuesday morning through the remainder of the forecast period. Drier air will reach the surface beginning Tuesday evening with forecast dewpoints to drop into the 50s by Wednesday morning. DNM && .AVIATION... (18Z TAFS) Issued at 1217 PM CDT Thu Sep 26 2024 A surge of moisture associated with Helene will be ushered into an upper level low later tonight that is forecast to be situated over the Mid- South. As this occurs, rain chances will increase across the region, eventually resulting in the reduction of visibilities and ceilings areawide. As these two systems interact, a tightening pressure gradient is forecast to occur, bringing the potential for wind gusts exceeding 30 knots at most terminals. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Flood Watch from 7 PM CDT this evening through Saturday morning for ARZ009-018-026>028-035-036-048-049. MO...Flood Watch from 7 PM CDT this evening through Saturday morning for MOZ113-115. MS...Flood Watch from 7 PM CDT this evening through Saturday morning for MSZ001>009. TN...Flood Watch from 7 PM CDT this evening through Saturday morning for TNZ001>004-019>022-048>055-088>092. && $$ PUBLIC FORECAST...DNM AVIATION...JPR