February 2, 2012

Tonight: Mostly cloudy with areas fog. Low: 25-30. Wind: E 5-10 mph.
Friday: Mostly cloudy. High: 38-45. Wind: NE 5-15 mph.
Friday Night: Mostly cloudy. Along and south of Highway 20: A 40% chance of rain/snow. Low: 26-32. Wind: NE 10-15 mph.
Saturday: Mostly cloudy. Along and south of Highway 20: A 50% chance of rain/snow. High: low-mid 30s.
Sunday: Partly cloudy. High: upper 30s.
Monday: Mostly sunny. High: near 40.
Tuesday: Partly cloudy. High: mid 30s.
Wednesday: Mostly sunny. High: low 30s.
Thursday: Partly cloudy. High: low 30s.
Early Afternoon Analysis: At noon, there is a wide range in temperatures due to the clouds and fog this morning in eastern Iowa. Temperatures in NE Iowa are as cold as 30F while central and western Iowa are in the mid 50s. The wind is generally less than 5 mph from the southeast. There are some areas with clouds and fog in eastern Iowa but there are holes developing.Western Iowa is sunny. See map below.

At the surface, there is a 1026 mb high stretched from Minnesota to Indiana. We are watching closely the 1010 mb low over New Mexico. At 850 mb, the temperatures are between 2-4C with a S/SW wind at 5-15 knots. At 500 mb, there is a ridge just west of Iowa putting in a northwest flow with the wind at 30-40 knots. There is a trough developing over Colorado and Utah. At 300 mb, the jet stream is following along the 500 mb pattern.
This Evening/Tonight: The sky will be mostly cloudy with areas of fog. Some of it can be locally dense. A DENSE FOG ADVISORY is in effect through Friday morning.

Friday/Friday Night: The sky will be mostly cloudy with a stray rain shower south of Iowa City late in the afternoon. Friday evening, as the storm moves east, rain will spread across the southern half of the viewing area (along and south of Highway 20). Late Friday night there will be a rain/snow mix again in the southern half of the viewing area. Northern areas will be mostly cloudy and dry. High pressure in the Dakotas will keep the storm from moving north and spreading the precipitation northward.
Saturday: Again the high across the Dakotas will keep the northern counties dry. The high will move east into Minnesota. The map below is for Saturday morning.

Here is the HPC depiction of the map Saturday morning.

The low will be located over southern Missouri and will move east and weaken through the weekend. Areas along and south of Highway 20 will see a mix of rain/snow change to light snow in the afternoon and evening. Snow accumulation will be 1” or less. The wind will increase from the northeast at 10-20 mph. High temperatures will be in the low-mid 30s. The map below is the amount of liquid out of this storm from Thursday evening to Saturday evening.

The maps below show snow potential of 1”+. This is for Friday evening to Saturday evening.

This is for Saturday evening to Sunday evening.

Here is the forecast track of the storm.

Extended Forecast (Sun-Thu): High pressure will be over Nebraska, Kansas, Missouri and Iowa providing lots of sunshine with mild high temperatures in the upper 30s and low 40s. A cold front will cross the state, from north to south, Monday night and the result will be a mix of sun and clouds Tuesday. The map below is for Tuesday morning.

High pressure from Canada will settle south across the Midwest and Great Lakes with dry weather and plenty of sunshine Wednesday. Another cold front is possible for Thursday but no moisture for it to work with…so just a mix of sun and clouds can be expected at this point.
Long Range Forecast (Feb 10-16): The Climate Predication Center hasIowa with near to above normal temperatures and near to below normal precipitation.


Posted under Forecast Discussion