Absolute Vorticity

May will start off dry this weekend for the KY Derby, but rain and storms quickly return Sun night thru the middle of next week. The Ensembles for the next couple of weeks continue to show above normal rainfall. May looks to be wet for the first half of the month anyway. Temp wise, I see a couple of dips still but mainly temps will trend above normal as we get more 70s and 80s ahead of each frontal system, and only a day or two in the 60s behind each frontal system. Low frost threat Sat morning at this time is still showing up.

Hey Les, here is a nice visual for your May forecast. As of right now - definitely looks very wet.

Thanks Mike for the visual... always helps!

An early look at Mother's Day is cool with temps in the low to mid 60s. That can change of course but a nice trough looks to be over us at that time as we get another one of those dips I've been talking about. (same kind of dip we get for this upcoming Sat morning - lows in the U30s)

I like a similar 1-2" call for the Sun night - Wed period of next week per GFS and Euro runs this afternoon. Pattern looks to be a repeat performance. Severe wx threat will of course be determined as we get closer.

Good evening all,

May is upon us and our first forecasting challenge is a frost threat Saturday morning. Does it happen? I think the upper 30s are possible for many but does anyone get to 36 or below? That is really critical for frost formation. If you stay above 36, your sensitive plants will likely be okay. (There are exceptions LOL) Anyway... rural areas I think probably have the best chance at this with 38-40 in the city is kind of my thinking at this point. If anyone wants to got colder, please chime in of course.

Then we get wet again with another 1-2" in the works Sun night thru about Wed of next week with another stalled out slow moving frontal boundary and waves of low pressure moving along it. With this last event, the LLJ provided a nice MCV and we saw a nice meso low pass thru Western and central KY. Us being on the north side, got the stratiform rains with embedded lightening and thunder. Can we build up some instability to get a further north track and have a stronger LLJ early next week versus what we saw for this last event? Rainfall amounts I think are going to be similar next week to this current event. Low lying areas and river / creek interests should monitor things of course.

Anyway to early to call on severe prospects but it's always a keep one eye open kind of things this time of year and be ready to open the other eye should things look to line up. As always, keep it here as you've done for the last 13 years.

Hi Les,

Up my way north of the I-70 corridor probably has the best chance i.e. of getting below 36 Sat morning.

ILN has issued a frost advisory for tonight for everyone:

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM EDT SATURDAY...

* WHAT...Temperatures falling between 33 and 36 degrees will
result in frost formation.

* WHERE...Portions of East Central and Southeast Indiana,
Northeast and Northern Kentucky and Central, South Central,
Southwest and West Central Ohio.

* WHEN...From 2 AM to 9 AM EDT Saturday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if
left uncovered.

tron777 wrote: ↑Fri Apr 30, 2021 6:35 am ILN has issued a frost advisory for tonight for everyone:

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM EDT SATURDAY...

* WHAT...Temperatures falling between 33 and 36 degrees will
result in frost formation.

* WHERE...Portions of East Central and Southeast Indiana,
Northeast and Northern Kentucky and Central, South Central,
Southwest and West Central Ohio.

* WHEN...From 2 AM to 9 AM EDT Saturday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if
left uncovered.

I know the rule of thumb is always plant tender vegetation after Mother's Day. However it is sooooo difficult when mother nature teases us with a stretch of warm weather and to add insult to injury, all the garden centers display their flowers and plants all saying "buy me"! LOL

I agree Mike. Still in wait mode here.

What does the first look at the timeline for the Monday and Tuesday rains/storms look like at this point? Thank you for your help!

Hi JR,

Right now I like Sun night into Mon for the first batch. A small break then another round sometime on Monday, thinking afternoon into the overnight. Then a third round on Tuesday. Ending on Wed. Kind of broad brushed here but we're a ways away before the timing can be nailed down better,

Let's see how long we can go to kick off May tonight. We've got the clear skies and the wind has come down now some from what we saw earlier. Wind should slacken off after midnight to allow for temps t o drop. With dews very low in the U20s to L30s across the area, temps of at least 33-36 range appears likely.

A closer look at the models for those who asked about timing... Sun night and Monday looks like lighter rain but the Tues afternoon and Tues night round looks to be the heaviest and best chance for any stronger t-storms. For Monday, the SPC likes the ARK LA TEX area for severe wx and nothing outlined yet for Tues, El Cinco De Mayo. My Birthday too so might be an interesting afternoon to watch unfold.

Starting out for the 1st day of May (May Day) progged for around 34 up my way Sat morning.

Nice rebound though with upper 60s / 70 degrees for the afternoon!

I got down to 33 this morning. CVG got down to at least 36. Maybe 35. Anyway highs around 70 can be expected today and 75 to 80 region wide tomorrow. Enjoy this weekend before we get wet. Oh and get your bets in! 6:50pm tonight on NBC.

SPC Day 3 update for Monday puts us on the board.

Currently 43 here in Greenville and progged for 68 to 70 later.

Headed up to Michigan for the weekend, will be back sometime tomorrow. Weather looks windy up there this afternoon but a wonderful Sunday 80+ just like we will see down here. Plenty of sunshine too.

One more possible frost threat Mother's Day weekend then maybe, just maybe are we done yet? I wanna start planting!

Low imby was 34.2, current is 51.8, so as expected, a nice warmup. Finally a dry Saturday. The last couple have been pretty wet!

Have a fun trip Les, safe travels! And happy early birthday!

WxMom wrote: ↑Sat May 01, 2021 10:17 am Low imby was 34.2, current is 51.8, so as expected, a nice warmup. Finally a dry Saturday. The last couple have been pretty wet!

Have a fun trip Les, safe travels! And happy early birthday!

Thank you Gina! Hope you and the fam have a lovely weekend!

12Z NAM shows a steady rain on Monday with very heavy rain Monday night after midnight. Ending 8pm Tuesday at CVG, we get 1.73"

tron777 wrote: ↑Sat May 01, 2021 10:00 am Headed up to Michigan for the weekend, will be back sometime tomorrow. Weather looks windy up there this afternoon but a wonderful Sunday 80+ just like we will see down here. Plenty of sunshine too.

Have a great trip and fun time, bro!

Currently 68 here in G'ville.

Mon - Tues ...

Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Wilmington OH
501 AM EDT Sun May 2 2021

INZ050-058-059-066-073>075-080-KYZ089>100-OHZ026-034-035-042>046-
051>056-060>065-070>074-077>082-088-031000-
Wayne-Fayette IN-Union IN-Franklin IN-Ripley-Dearborn-Ohio-
Switzerland-Carroll-Gallatin-Boone-Kenton-Campbell-Owen-Grant-
Pendleton-Bracken-Robertson-Mason-Lewis-Hardin-Mercer-Auglaize-Darke-
Shelby-Logan-Union OH-Delaware-Miami-Champaign-Clark-Madison-
Franklin OH-Licking-Preble-Montgomery-Greene-Fayette OH-Pickaway-
Fairfield-Butler-Warren-Clinton-Ross-Hocking-Hamilton-Clermont-Brown-
Highland-Adams-Pike-Scioto-
501 AM EDT Sun May 2 2021

This Hazardous Weather Outlook is for East Central Indiana,
Southeast Indiana, Northeast Kentucky, Northern Kentucky, Central
Ohio, South Central Ohio, Southwest Ohio and West Central Ohio.

DAYS TWO THROUGH SEVEN...Monday through Saturday.

Strong to severe thunderstorms are possible late Monday into
Tuesday. The primary threats are damaging winds and large hail.

SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed following local, state, and CDC guidelines.

$$