Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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
590 FXUS61 KCLE 181731 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 131 PM EDT Tue Jun 18 2024 .SYNOPSIS... An upper level ridge will persist over the region through this week, resulting in widespread near-record temperatures across the area with isolated to scattered thunderstorms possible each day. The next system won`t arrive until the end of the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... 1:30 PM Update... Similar to yesterday, pop up thunderstorms are developing across the region this afternoon. Temperatures in the upper 80s to lower 90s with dew points in the upper 60s to lower 70s have allowed for a corridor of 2500+ J/kg of MLCAPE to develop essentially along and east of I-71. Fairly moist column of air with PWATs in the 1.5 to 2 inch range in combination with slow moving/back building storms will lead to some hydrological concerns in addition to the severe threat this afternoon. Still anticipating for these storms to diminish this evening with the loss of daytime heating. 9:45 AM Update: Gave the temperature/dew point forecast (and resulting apparent temperatures) a decent look for today. Dew points across parts of the area were slightly lower than the prior forecast (though are still in the upper 60s/lower 70s and will remain similar through the day). Temperatures were near or slightly warmer than the prior forecast, though a good amount of clouds across Northwest and North Central OH will cap high temperatures a bit compared to yesterday. Didn`t make large changes to the temperature forecast though did lower the I-75 corridor and down towards Marion about a degree. All in all much of the area should see heat index values top out between 95 and 102 today. The other forecast item of note this afternoon and evening is shower and storm potential. A somewhat more moist column than yesterday may lead to somewhat higher coverage of storms this afternoon than Monday, though slightly tempered heating due to clouds and perhaps a bit less downdraft CAPE than Monday could limit severity of storms a bit. Overall, the Marginal Risk for wind (and perhaps a bit of hail) is reasonable. Likely will be several possible foci for storm initiation by midday or early afternoon...ranging from differential heating on the eastern edge of thicker clouds spreading in from the west, a lake breeze from near Cleveland points east, and modest terrain- enhanced convergence over the central highlands. This will likely lead to a somewhat chaotic/scattered evolution of storms amid an environment with otherwise weak forcing and shear. This could lead to locally slow-moving/training/back-building storms with heavy rain in this humid environment. Storms will gradually subside with the loss of heating tonight. Previous Discussion... Going to use some degree of a persistence forecast here on the periphery of the dominant upper level ridge that has provided the first day of heat in what will be a week of above normal temperatures. The more recent forecasts have seen either an increase in the low/mid level moisture supporting convective cloud growth, or that the models are finally resolving what was always going to be there much better. Satellite imagery is showing a solid connection to a tropical moisture feed from the Gulf of Mexico/Bay of Campeche providing the moisture for the convection. Plenty of SBCAPE from high dewpoints and air temperatures in this environment to get scattered thunderstorm activity for the entire region, again, in a south to north type flow. With relatively freely rising parcels in surface to 700mb lapse rates eclipsing 8C/km, some drier air aloft and inverted V soundings will lend to another day with wind gust threats despite a relative lack of shear. Pockets of low level f-gen help with initiation as will a couple of weak waves aloft. Temperatures on the high side again and will leave the Heat Advisory in place, but precipitation cooling and cloud cover will keep some locations in check in terms of temperatures. Some locations not affected by this could still get into the mid to upper 90s once again. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... The heat wave and headlines will continue through the short term period with daily afternoon heat indices in the upper 90s to lower 100s. Not much relief is expected at night either with low temperatures in the 70s. Only real change to the forecast is an increased risk for afternoon isolated strong thunderstorms on Thursday and Friday as moderate to strong instability will pool across the southern and eastern Great Lakes. Weak shear less than 20 knots is expected, so anticipate any thunderstorms that do develop will be poorly organized and generally short-lived. These storms will primarily carry a damaging wind risk given steep low-level lapse rates and large theta-e differences. && .LONG TERM /FRIDAY THROUGH MONDAY/... One last surge of extreme heat may arrive on Saturday ahead of an approaching upper-level low across the Upper Great Lakes. The current headlines may need to be extended a day further through Saturday as heat indices reach the upper 90s to lower 100s in the afternoon. Moderate to strong instability across the Lower Great Lakes may result in isolated strong thunderstorms on Saturday, though anticipate any storms that develop to be poorly organized and generally short-lived given the weak shear in place. The better potential for more organized strong thunderstorms will arrive on Sunday as a well-defined upper-level low moves east across the Upper Great Lakes, extending a surface cold front through the area. Moderate to strong instability appears to remain in place combined with 30 to 35 knots of southwesterly mid-level flow. Behind the front, more cooler and more seasonable weather will arrive, with temperatures in the low to mid-80s on Monday. Anticipate dry weather conditions as a surface high briefly builds in across the Great Lakes. && .AVIATION /18Z Tuesday THROUGH Sunday/... Have VCTS at all TAF sites this afternoon to account for ongoing pop up convection. The best location for continued storm development looks to remain along and east of I-71 and along the I-80 corridor. Have placed TEMPO groups for TSRA impacts at KCLE and sites east. Expectation is for these storms to decrease in intensity and coverage by 22-23Z tonight as we lose daytime heating. Winds remain southerly through the period less than 10 knots with the exception of higher wind speeds and gusts in any thunderstorms at terminals. Outlook...Primarily VFR expected through Friday. Isolated thunderstorms are possible Wednesday afternoon. && .MARINE... A generally quiet marine forecast is in store for Lake Erie as a large upper-level ridge remains across the Eastern CONUS, resulting in limited surface flow. Only concern will be in the afternoon and early evening hours this week as daily isolated to scattered thunderstorms could bring strong wind gusts and small hail. && .CLIMATE... A prolonged stretch of hot weather is expected this week. Temperatures are forecast to approach or exceed record highs on several days. The records for Tuesday, June 18 to Friday, June 21 are listed below for our official climate sites. Date Toledo Mansfield Cleveland Akron Youngstown Erie 06-18 98(1994) 93(1994) 96(1944) 96(1944) 95(1994) 92(2018) 06-19 98(1995) 94(1994) 92(1995) 94(1994) 94(1994) 92(1931) 06-20 98(1953) 94(1988) 96(1988) 95(1933) 95(1933) 92(2016) 06-21 100(2022) 96(1988) 95(2022) 97(1933) 98(1933) 95(1933) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Heat Advisory until 8 PM EDT Friday for OHZ003-006>014-017>023- 027>033-036>038-047-089. PA...Heat Advisory until 8 PM EDT Friday for PAZ001>003. NY...None. MARINE...None. && $$ SYNOPSIS...26 NEAR TERM...Iverson/26/Sullivan SHORT TERM...Kahn LONG TERM...Kahn AVIATION...Iverson MARINE...Kahn CLIMATE...