THAT'S ENOUGH OF THAT...

Wind, wind, and more wind. Like it or not, we live in a part of the world where wind is an impactful factor any time of the year. The spring transition season is prime time for wind, due to the lingering presence of winter's cold and the arrival of the warmer air that leads to summer. This doesn't happen at the snap of your finger, it's a timely process that takes months. For those that don't know, if earth's temperatures were the same everywhere, there would be no wind. Thermal contrasts create wind, and the greater they are, the stronger they get. Wind is the planet's way of attempting to equalize the temperature imbalance found in the mid-latitudes.

The one area where wind is not much of a factor is in a zone 5 degrees north or south of the equator known as the doldrums. Near steady state temperatures keep pressures uniformly light and winds relatively calm outside of squalls. This windless space is also known as the intertropical convergence zone.

As you can see below, the one time of year that winds drop significantly locally is July and August. Summer is in full force and cold air intrusions are at a minimum. April is the windiest month of the year in Cedar Rapids, with an average speed of 12.3 mph out of the north. In May, winds transition to S/SE and finally in mid-summer they are S/SW. Come August, average wind speeds have dropped by half to 7.1 mph. Come October, the return of cold air masses quickly ramps wind speeds up to 11 mph or greater, with a turn to the W/NW.

My point in all this is to show we are still in peak season as far as winds are concerned. All it takes is a quick transition in temperatures up or down, and winds will follow. Monday, that came in the form of a cold front and an upper level pocket of cold air that you see spinning SE on the satellite.

Look closely on the satellite in eastern South Dakota and you can see an eye like feature digging SE towards NW Iowa. That little mesoscale low was associated with cold air aloft. Not only did it drive showers (greater coverage in that vicinity), it spread cold air aloft into the Midwest. While temperatures hit 60 at the surface Monday, readings a mile up at 850mb were near or slightly below freezing. That massive contrast created steep lapse rates that enhanced an already tight pressure gradient. The cold air advection also allowed deep mixing, enabling winds to do their thing once again, reaching speeds of 38-45 mph. The peak gusts of 45 mph were measured in Waterloo and Dubuque Monday evening. Frankly, I'm tired of wind.

That said, cold air advection remains vigorous Tuesday and another gusty day is ahead with speeds of 30-40 mph on tap. Highs of 53-58 are expected, with wind chills through noon remaining in the upper 30s to low 40s in the NE. 40s to 50s is expected elsewhere. Enough said. These are wind chills around 10:00am Tuesday.

Wednesday we get a pretty decent day. Winds will gradually increase out of the S/SE in the afternoon, with much of the day spent in the range of 5-15 mph. Temperatures in the low to mid 60s will be seen under mostly sunny skies.

ACTIVE WEATHER AHEAD

Thursday, a trough develops over the west that over several days ejects multiple pieces of energy with the ability to be shower and thunderstorm producers. Saturday evening the 500mb jet has morphed into this configuration which is good for the transport of moisture.

The first impulse arrives with its warm air advection Thursday afternoon and evening. A round of showers and storms is expected to form ahead of a warm front that inches into eastern Iowa. These are likely to be elevated, and thus the severe weather threat seems low end. Models are not bullish on widespread heavy rains, but if we can scare up some storms, some 1/2"+ totals are possible Thursday night. We need a few more details to assess this accurately.

Friday could be a bit more interesting, but it's highly contingent on the front and a wave of low pressure that travels along it during the day. A triple point is shown reaching EC Iowa in the afternoon with warmth and moisture ahead of it. The EURO pops highs into the low 80s from the Quad Cities southeast. An earlier frontal passage in the NW keep highs confined to the upper 60s.

Dew points are shown reaching the low 60s in most spots around noon, but recent trends show a cold front racing through the area by mid-afternoon. Despite some decent instability east of the Mississippi, it looks like the front will clear before any significant storms develop. The EURO indicates CAPE up to 1500 j/kg in my far eastern counties Friday afternoon, indicating that's the location to look for regarding any strong storms.

Bottom line, timing holds the key to any storms Friday and with new guidance speeding up the arrival of the front, chances have decreased outside my far eastern counties in Illinois. Just another thing that needs more time on the stove to see how it all turns out in the end. If nothing else, the end of the week looks warm and a bit muggy.

That disturbance exits Friday night with the passage of a cold front. Temperatures take a tumble Saturday and so do the dew points, dropping from the 60s to the 40s. It's bye, bye warmth and humidity. It will also be a dry day Saturday, with highs in the upper 50s to low 60s.

The focus then turns to Easter Sunday and a storm that could be a severe weather producer. The latest trends have a dynamic system approaching from the south during the day. The warm moist air of Friday tries to return ahead of the surface low and associated warm front. However, the trend of a slower arrival is evident, allowing my area to stay well removed from the warm sector and any serious severe weather. That should remain confined to Missouri and southern Illinois. The trade-off is a far from perfect Easter. With brisk winds out of the east, and low clouds in the morning, Easter starts off breezy and chilly. Eventually, showers (and embedded thunderstorms south) spread northeast in the afternoon. The GFS shows highs in the mid to upper 50s. Since Easter is late this year, I had hoped for a warm one, but that does not look at all likely in this situation.

While the end of the week looks challenging, Tuesday will be worth a coat as chilly temperatures and brisk winds hold spring conditions at bay for another day. Roll weather....TS