Tuesday, July 31, 2012

Tuesday July 31 Update

Good Tuesday!  Not much change to tell you about for the next couple of days.  A very weak front will slide through the area tonight...but don't expect much change in temperatures or humidity.  Could be a stray shower tonight, but chances are in the 10% range. We'll see more near 100 heat for tomorrow and Thursday, before some slightly more promising changes enter the picture.

As we head toward the weekend, the big ridge to our west will begin to flatten out and a fairly promising shortwave trough will lead to some better rain chances.  The ECMWF (European model) has performed pretty well this summer, and here's what today's 12Z run is showing as far as precip....

Friday:


Saturday:


Sunday:


Not to be Debbie Downer, but with our ongoing exceptional drought....I've taken a bit of a "believe it when I see it" approach to forecasting rain....but seeing the Euro cranking out precip makes me think we may have something to look forward to.  The HPC 5-day rainfall forecast today is more optimistic that yesterday:

Stay tuned for more on upcoming rain chances over the next couple of days.

Finally, today we say goodbye to what has been, in the words of Laura Emerson, an "evil hot" month.  We topped 90 degrees on 28 of 31 days this month, and hit at least 100 degrees a whopping 11 days!  That makes a total of 57 days at or above 90 degrees this year, and a record-setting 15 days at or above 100 degrees!  So will August offer any changes??? Well, according to the latest outlooks from the CPC, the answer is no.  The August outlook continues to highlight above normal temperatures over a large part of the U.S.


And as you might expect, the outlook also calls for things to stay dry...


Have a good day, and here's your latest Weather Authority 7-Day Planning Forecast:


Monday, July 30, 2012

Monday 7/30/12 Update

For the first time in months...a new update! The blog has been in semi-retirement for a while, but look for more frequent updates again here.

Like we've seen the past few days, small chances for showers and thunderstorms are in the forecast for this evening and tonight as a disturbance moves down the MS River from the northwest.


Some echos on radar from Farmington to Mt. Vernon may bring some thicker clouds and maybe even sprinkles or light showers to parts of SEMO & S IL this evening....not terribly confident that it will hold together much farther south of the Ohio River.  That said, this disturbance is headed toward some pretty unstable and juicy air across parts NW TN, where the SPC has issued a slight risk of severe storms tonight:


One of the forecast models that has done well in recent days of forecasting short-term storms shows some convection firing up later tonight in the southern parts of the area....here's the 17Z run at midnight tonight:


Given that we've already got a little rain entering the picture late this afternoon, and that similar scenarios the past couple evenings have lead to some scattered showers, I'd say this model is probably onto something.  Any storms that develop, if they can become rooted in that moist/unstable air, could produce wind and hail up to severe limits (58 mph/1"diameter).

Moving on, last week my colleague Jennifer Rukavina got a chance to speak with KY state climatologist, Dr. Stuart Foster about a few topics....and he shared some eye-popping numbers about our ongoing drought.  For the months of April-July, the NWS Paducah has measured 3.46" of rainfall.  That is easily the lowest amount for that period on record....the previous driest for April-July was 4.41" in 1914.  Unreal.

The outlook for the coming days doesn't offer much in the way of change.  Here's a look at the upper-level charts (jet stream) for the next couple of days:


Notice the H with the white lines around it right in the middle of the maps?  That is the center of the ridge that is responsible for the persistent heat.  For the next couple of days, we'll continue to find our region right on the eastern edge of that ridge...close enough to the core of the heat that we'll be plenty hot and humid (upper 90's/heat index 95-105)....but also in a tricky northwest flow pattern, where another one or two minor disturbances could slide down the MS River Valley and keep a small chance of storms in the forecast (20% Tuesday, less than 20% Wed/Thu).



Looking ahead to the end of the week and weekend (surface chart above), it's generally more of the same...hot, humid, and small chances of storms. However, by Sunday and Monday, a cold front looks like it will attempt to nudge into the region....this may bump us up to the 30% shower/storm chance range and knock a couple of degrees off high temperatures....but this front will most likely wash out over our region.  Rainfall totals over the next 5 days continue to be discouraging to say the least:

Finally, we are inching closer to the September peak of the Atlantic hurricane season, and there is a chance of business picking up over the next few days.  A new disturbance way out to the southwest of the Cape Verde Islands is being analyzed for development....the National Hurricane Center is giving it a 20% chance of becoming a tropical storm over the next 48 days.  Here's the latest computer model tracks showing where it could go through Monday:


Have a good one!

TO