Friday, March 30, 2007

Severe Potential (3/31)

The day 2 outlook this afternoon from the SPC indicated that severe weather was a decent probability over the state tomorrow. Slight risk with 30% probabilities were the exacts, the first day 1 outlook on this event should be issued within 2 hours. Tonights' models are currently making their way into the picture, with the NAM already complete. GFS has been the favored model due to the better handling of the low position as well as frontal positions throughout the entire system this week. I'll hopefully post an update later once the GFS is complete as well as the day 1 outlook is released.

The setup tomorrow may not look spectacular when viewing some of the supercellular parameters, however with such a strong cut-off low pressure system that is winding its' way up into the area the severe potential definitely exists. Very strong lift and vorticity will work its' way into the area during the afternoon hours. Instability will be of interest, depending on how much sun can peak out in the early afternoon and get things warmed up. Shear values should be sufficient, especially along the boundary intersections and near the low. Large hail as well as damaging winds are the main threats mentioned at the moment, however the tornado risk will likely be there. A lot of problems pinpointing the risk as it is doubtful to be looking at a widespread event, better chance at localized areas being prime for the severe weather. Thus all of the state of Iowa, as well as northern MO and Illinois should watch this system to see where it sets up the best potential.

Update Likely Late Tonight... As Well As Early Tomorrow Morning...

Tuesday, March 27, 2007

Rainy Days

Long time since the last update and it may be awhile until the next, possibly this weekend. Busy week ahead and currently, but at least instead of the warm and near hot temperatures outside which was distracting from studying it has now turned into a cloudy and sometimes rainy week. That should be helpful to the studying...

Sunday as well as Monday saw temperatures rise into the 70s and 80s throughout the state, nearing record levels as we were 30 degrees above normal for this time of the year. Temperatures have begun to moderate some thanks to the cloud cover that is expected to be in place much of the time. A weak system is currently hanging out over the state and will likely stay here until the strong system coming into the plains tomorrow finally makes it through Iowa. That may not happen until this weekend though, as it seemingly floats around the plains' states for quite a while. This is going to the cause of your continuous chances of rain that is in the forecast from today through Sunday. Thunderstorms are going to be possible as well, Wednesday evening and then Thursday being the better chances. With a decent shot at thunder across the state once again on Friday, this weekend is still up in the air. The severe threat is a complicated situation as well, beings this system is essentially stalling out it could have some radical movement and thus making it hard for the models to come into an exact agreement on some sort of things. If there becomes the risk for any significant severe weather over the state I will make time for an update...

For now, enjoy the above average temperatures even with the rain and cloudiness. We may likely be back down to the freezing mark later next week, at least for the lows.

Wednesday, March 21, 2007

March 21 Severe Weather

A slight risk has been issued by the SPC for severe storms over much of Iowa this afternoon/evening and into the overnight hours in some parts of the state. The main reason for these storms will be a cold front that will move into the area from the north this afternoon, potentially causing thunderstorm development if it has not already occurred. Some storms during the late afternoon may fire on their own just ahead of the cold front, these storms are most likely to happen in southeast Nebraska and southwest Iowa. Threats with those storms will include large hail, damaging winds and an isolated tornado or two given the discrete nature of the storms. By late evening and into tonight, it is more likely that a line of storms will have developed across much of Iowa into Nebraska and even Kansas. This line may still produce some large hail as well as damaging winds over the state, especially the southeastern half.

Currently, temperature and especially moisture is on the rise throughout the state. Thunderstorms are noted to be affecting parts of northeastern Iowa this morning as well as central Iowa. The storms in central Iowa are currently fairly strong, especially just to the west of Winterset, IA at this time. These storms are moving northeast and will likely affect the Des Moines metro later this morning. No warnings are out, although some small hail may be possible if the storms continues to strengthen slightly. Also, lightning strikes are being reported from the cells to the southwest of Des Moines and may also be a concern to some.

Tuesday, March 20, 2007

Spring has Arrived!

Well the official start of spring occurs today, with temperatures around the state rising quickly thanks to the southerly winds and abundant sunshine. Highs should range from near 50 to the mid 50s, with lows tonight only dropping to the lower to mid 40s. Both of these are above normal for the current time of year. Continued advection of warm air and moisture should continue on Wednesday, allowing highs to range from 60 to near 70 potentially. Of course the mention of increased moisture should allude to something, that is the chance of precipitation. Luckily, the wintery stuff looks to have come to an end and the chances of not only rain showers, but thunderstorms have came into the picture! The chances for rain/thunderstorms should continue from tonight and Wednesday night into Thursday monring and then another round during the weekend. This weekends round should range from Saturday night through the rest of the weekend and possibly into the beginning of the work week. Once again, those chances look to include the risk of thunderstorms over the state. Temperatures during this time don't look to fluctuate greatly, with highs consistently in the 50s and 60s. Lows should range from upper 30s and mid 40s in the first half, while the weekends' lows stay in the 40s and 50s.

As mentioned, the risk of thunderstorms during the forecast period makes for another good conversation piece. The heavier rain may cause some flooding as rivers are already fairly high in several areas across the state. One of the better risks, at least in the mind of several who read the blog is the risk of severe weather over the area. Wednesday evening/night looks to be the first risk, with the SPC already including much of Iowa in a slight risk and increased probabilities of severe weather. This mornings outlook increased to a 30% probability over the state, risks of large hail & damaging winds are the main ones. Tornado threat doesn't look to be great, but as of now it cannot be ruled out to have a storm or two become capable. A more in depth post on the risks tomorrow will likely come out later tonight. The second risk of potential severe weather is rumored to come next week. The specifics of this one are widely up in the air, but a watchful eye on the extended model runs does show a good system next week. I'll refrain from any comments on that one, as it will change undoubtedly. Look for the first severe weather forecast of the year tonight as the risk comes in Wednesday.

Thursday, March 15, 2007

Fluctuating Temps...

The first 2 days of the week saw temperatures well above normal and at record levels across the state, ranging from the 50s to 70s on Monday. Tuesday saw the temperature range from the 50s to the 80s in some areas, breaking several records. Yesterday however the sun didn't appear quite as much as the previous days, plus the help of a north wind held the temperatures in the north in the upper 30s. Areas of southern Iowa however continued the sun and saw the mercury rise into the upper 50s and 60s, with a few 70 marks. Today the whole state is behind the front that went through, with cloudy skies scattered across the state. Temperatures today are only in the upper 30s and upper 40s as of Noon; Expect highs in the lower 40s and lower 50s however by the time the sun sets.

Looking through the weekend, high temperatures should slowly rise once again as warm air advects into the plains. Fridays' highs in the 40-50 range with only a couple of degrees increase on Saturday across the state. By Sunday the warm air really begins to flow into the state from the southwest, seeing highs range from 45 in the northeast to near 65 in the southwest. Lows during this time should also moderate, with tonights ranging from the teens to 30s. By Sunday night, lows should only be dropping into the mid 30s or only 40.

As far as precipitation goes, nothing significant is in sight. A weak wave moves over western Iowa on Friday night that could bring some light rain/snow. Another weak wave could affect the other side of the state on Sunday, where some rain or rain/snow mix could be seen across the northeastern half of the state. Otherwise it'll be later next week before another decent system heads over the plains.

Monday, March 12, 2007

Spring's Here!?!

It certainly seems like it anyway with temperature rising throughout the state rising well above normal and even to record levels. Currently as of 2 PM this afternoon the state has temperatures ranging from 72 to 39 degrees. The southeast corner of the state has the highest temperatures while the north-central part of the state has the lowest temperatures. The large range is likely due to the patch of clouds that is working over the state, causing some areas of north-central Iowa to be well below other areas of the state that are receiving sunshine.

Expect highs tomorrow to be slightly higher than today in some portions of the state, while others should be about the same. The southern half of the state should be near 70 or higher while the northern half should see temperatures at 60 or greater. With no cloudiness in the morning, temperatures should rise rapidly in areas of the state that aren't quite as warm today. Wednesday should see temperatures starting to fall once again, with highs ranging from 50 to 70 degrees north to south. Thursday will have temperatures dramatically dropping, ranging only from low 40s to mid 50s. Friday will have temperatures drop a couple more degrees before the gradual increase begins once again by this weekend.

Lows throughout the week will range from 40 to 50 tonight, mid 30s to 50 on Tuesday night and continuing to drop the rest of the week. Only 30 to 40 degrees on Wednesday night and 20 to 30 degrees on Thursday night. Friday night into the weekend has lows maintaining the 20s and 30s in the state with gradual increases.

The only precipitation chances look to come with two weak systems that will clip the area. The first one may clip areas of northeast Iowa on Tuesday night, only small chances of rain or rain/snow mix. By Wednesday the precipitation may move across most of the state with mainly rain, however some areas of the north may see a rain/snow mix. There doesn't look to be any significant precipitation with either of these chances, but areas of the north should watch for slick conditions if there is some rain/snow mix.

Tuesday, March 6, 2007

Warm & Quieter Week

This week looks to be a much better week and coming weekend then the past couple of weeks. No major systems look to be eying the plains, although there are some small disturbances that may create some weather. The main thing through this week is going to be the increase in temperatures and that will be the first highlight of this update. Today's highs weren't that impressive, actually below normal by 5 to 10 degrees across the state. These temperatures should increase by weeks end, with tomorrow only a degree or two warmer than today. Thursday should see the big warm up start, with highs ranging from the upper 30s in the northeast to near 50 in the southwest! That a 10 degree jump from the previous days' highs... Friday will have highs ranging from 40 in the north to 50 on the southern border. This weekends' temperatures should range from 40 to 50 once again on Saturday; lower 40s to some readings in the mid 50s possible on Sunday before the next work week begins. A notice on these temperatures, they may range significantly depending on snow melt progression through the week and weekend. Some areas of the state may clear the snow out quicker than others and thus have highs significantly higher than other areas...

As for precipitation, several small disturbances could move through portions of the state this week. The best one likely Thursday night into Friday where some light rain and light freezing drizzle seems possible across the state. The light freezing drizzle would be likely seen in northern Iowa if seen at all in the morning hours on Friday. Tonight areas of the northeast may see some light snow, no accumulations seem likely right now though.

Saturday, March 3, 2007

Recap: Winter Storm (2/28-3/3)

Extended the date of the winter storm due to the winds sticking around and some light snow that enabled the blizzard warning to be extended to 6 am this morning and a Blowing Snow Advisory still in effect currently. Snowfall totals varied widely across the state as some portions received nearly constant snowfall on Thursday afternoon and other parts of the state were affected by the dry air that moved within the low and thus caused a lack of snowfall. Despite the lack of snow over some areas, blizzard conditions were still felt with winds gusting up to near 60 mph Thursday afternoon through Friday. Winds continue to howl from the north/northwest even today and thus why a Blowing Snow Advisory was issued for this afternoon.

Iowa Snow Totals Map

Where the heaviest snowfall occurred in western Iowa, roads are still not in good shape as several remain 'Travel Not Advised'. There is even a couple small stretches that remain closed at this time as crews are continuing to work non-stop to clear roadways. Luckily, there are no other major systems within sight and thus maybe relief is on its' way in a form of warmer temperatures. Highs over the next week should be well above freezing, with mid 40s here in Ames being likely. Thus the rest of the state should see 40 degree temps at least, with some lower 50s likely in eastern Iowa where less snow is on the ground. This warm-up may not be completely welcome though, as if any quick melting occurs the flood threat will increase quickly. As problems were already beginning in southeast Iowa before this storm, more snow upstream with melting could quickly escalate the flood threat.

Ames didn't receive as much snow as areas just to the west, but still dealt with plenty of problems. Roads throughout the area were closed as drifts were high enough to strand cars throughout the middle of the road. Despite this, Iowa State University held classes on Friday without plenty of staff and students being able to make it. This is after they closed early on Thursday without any great knowledge that the snow/wind wouldn't arrive until later that evening. For a view of what occurred Thursday evening, I have a time lapse video up from approximately 5:15 PM to 9 PM of the view out my window:

Time Lapse Video

No major storms in sight, thus a relaxing weekend and next week with the views of Spring Break gleaming in the following week.

Thursday, March 1, 2007

Winter Storm (2/28 - 3/2)

3/1 Update #10 - 9:30 PM

Snow continues in Ames as well as much of Iowa with wind gusts ranging from 25-40 mph with gusts being reported as high as 60 mph. This no matter how much snow is on the ground and falling is causing blizzard conditions throughout the area. Despite only have 2-3 inches in Ames, conditions here and surrounding roads are nearly impassible. In fact reports have came in that Highway 69 north of Ames has vehicles that are stuck on the roadway and abandoned due to being stuck in drifts. Story county officials have pretty much indicated that all roads should not be traveled tonight. All roads in western Iowa and central Iowa from Des Moines north are indicating that travel is not advised. Some of the more notable snowfall amounts include 14 inches in Estherville, IA; Atlantic, IA also 14 inches; NNW of Fort Dodge has 12 inches; Carroll/Denison area also has 14-16 inches.

Expect light to moderate snow throughout the night, accumulations 1-3 inches likely as the snow continues and winds stay steady at 30-40 mph with gusts up to 50. Many schools across western/central Iowa are already delayed or canceled. I do have a short time lapse video of Ames, IA from around 5 PM to 9 PM that I will try to get uploaded as well shortly...


3/1 Update #9 - 5:00 PM

Snow band now setting up from Ottumwa, IA northwestward through Emmetsburg, IA and even further. This band will work southeast through the next several hours as it is seemingly tapping into strong moisture. Expect moderate to heavy snow with this band, winds 25-35 will likely make this near blizzard conditions with visibilities less than a 1/2 mile. Interstate 35 is being closed from Ankeny to Ames as well, travel no longer being advised anywhere near Ames. Snow accumulating on roadways now as it is falling quick enough, thus expect rapid accumulations. Next update not likely until late tonight (approx. 9 PM)...


3/1 Update #8 - 4:30 PM

Several roadways, including I29, I80 and I35 remain at least partially closed throughout the state. National Guard is supposedly out on some portions of I80 looking for stranded motorists, Highway 20 in northwest Iowa has been closed due to the road being treacherous and semi's jackknifed blocking most of the roadway. Moderate snowfall occurring in Ames once again with very light/small flakes falling, keeping visibilities under a 1/2 mile. Blizzard Warning still in effect for Ames, although snow totals likely to only be 3-4 inches as mentioned before. Travel still not advised and Iowa State University yet to make a decision on classes tomorrow...

New Pressure Low: Vinton, IA @ 4:24 PM -- Pressure 28.87 (977.5 mb)


3/1 Update #7 - 3:00 PM

Snow has tapered off for the time being in Ames, with nearly no accumulation on the roadways thus far. Still expected to receive 3-6 inches by tomorrow morning with lingering snow expected tomorrow. Right now it seems as if some of the lows' moisture is being cut off and not as much wrap around precipitation is occurring. Winds are still quite strong and areas that have had snowfall are in some bad conditions. Expect winds to continue around 30 mph with snowfall off and on throughout the afternoon and into tonight. Likely accumulations around 3 inches seems best bet to me with the lack of moisture currently noted around the low...


3/1 Update #6 - 1:30 PM

The low pressure system continues to strengthen, now with the lowest pressure being found in Grinnel, IA at 28.89 inches of mercury or about 978.2 mb. Light snow now in Ames with not much accumulation on roadways beings they were so wet previously. Expect the snow to pick back up with the next band that should rotate around by 2 PM. Checking out the latest RUC forecast doesn't look that great as far as holding up to our 'blizzard' conditions that are forecasted. Not as much moisture seems to be present, thus I think this mornings snowfall might have been the best we see despite the low pressure strengthening this afternoon. Winds will pick up, but the snow just won't be as heavy looking at latest forecasts and current radar. Ames is likely looking at 3-6 inches of snow with the winds, which may still be enough to warrant the blizzard warning if the snow can come down heavy enough and not the light snowfall like we've seen the past hour.


3/1 Update #5 - 12:40 PM

Short update here, just to mention that the snow has now begun to fall in Ames, IA. Other reports as of late include a 6 inch report from Pocahontas, IA; 5 inches in Jefferson, IA; Audubon, IA also has a report of 8 inches... The winner thus far is Libberdale, IA in Carrol county with a report of 10.5 inches. But, as I type a new report has came across from Denison, IA and it is declared the new winner with 7.5 inches of snow in the past 2 hours with total accumulations of 14-16 inches!!


3/1 Update #4 - 12:30 PM

No major updates as of now, snow should begin over much of the central part of the state within the next hour. The sheriff's department has stated that they do not recommend travel anywhere in the western or northern part of the state. Snowfall in parts of western Iowa is likely to be even higher than originally forecasted with reports likely over a foot by this evening and still more snow to come overnight. The low pressure system is slightly north than forecasted, thus areas such as Ames might not see quite as much snowfall as we could have. Nonetheless, snowfall when falling will be aided by strong northwest winds which are already noted to be greater than 30 mph across much of western IA/eastern NE.

You can watch how the snow continues and how conditions look over much of central Iowa by viewing the IEM Webcams.


3/1 Update #3 - 11:00 AM

Continued road closures include I35 from Highway 30 north to the MN border now being closed. The low pressure system continues to drop in pressure, latest report from Chartion, IA indicates the low at 980.4 mb. To the west of the low winds have increased considerably, now indicating up to 30 mph average wind speed. Also to note, Iowa State Univ. is now closing at 1 PM today due to the deteriorating conditions.


3/1 Update #2 - 10:30 AM

Severe winter weather continues, Iowa roads begin closing. Nearly all roads in western Iowa have been limited with no towing help being provided as conditions worsen. Notable roads that are now closed as of just after 10 am include Interstate 29 throughout the entire state, I80 from the Nebraska border to Exit 100. Highway 71 & Highway 59 are both under 'No Travel Recommendation' throughout the entire state as well. Roads in central Iowa are reported as being mostly covered, while roads in the east are mainly wet. For constantly updated road reports, please use the Iowa Road Conditions Website.


3/1 Update #1 - 9:45 AM

Radar is currently running and is updating online on my homepage, radar showing strong reflectivity's from Greene county off to the northeast to Franklin & Butler counties. The precipitation at those areas is currently falling as rain/sleet mixture just as it is currently in Ames, IA. Heavy snow is being reported in northwest Iowa as well as along the IA/NE border. This should continue throughout the day and as temperatures drop as the low continues to move east/northeast the remainder of western/central Iowa will see the changeover to snow. Currently the low is centered near Osceola, IA with a pressure down to 983 mb; down 1 mb from last hour.

GFS & NAM are both indicating over a foot of snow is still possible in western Iowa as well as north-central Iowa. Winds are already 10-20 mph with expected increase as the low pressure system strengthens during the afternoon. With rain coming down at first and pavement temperatures very near freezing, expect a glaze of ice is possible first before the snow takes over. Updates will continue on this post throughout the day...