Forecast: November warmth continues

Posted at 4:00 PM on November 6, 2009 by Paul Huttner (0 Comments)

CPC 6-10 day outlook favors continued above average temperatures for the Upper Midwest.

Ah...Indian Summer in Minnesota.

The hum of leaf blowers everywhere. Dogs and cats blissfully strolling with lackadaisical owners down leaf lined boulevards. High School and Gopher football played outdoors under favorable skies. Weather folks babbling about temperatures 17 degrees above average. This is how early November was meant to be.

It's nice to see thermometers pushing 72 degrees in Windom and Canby. We hit at least 63 here in the Twin Cities, we'll know after 6pm if we crept as high as 64. The NWS forecast discussion today confirms my thinking that we could have easily hit 65 to nearly 70 if we had not had those pesky cirrus clouds today.

"OUR AFTN TEMPERATURES COULD HAVE BEEN TWO TO FIVE DEGREES WARMER IF CIRRUS SHIELD DIDN`T MOVE ACROSS THE AREA DURING THE HEAT OF THE DAY. EVEN WITH THE HIGH CLOUDS...TEMPERATURES HAVE MANAGED TO RISE 5 TO 15 DEGREES ABOVE NORMAL FOR EARLY NOVEMBER."

It looks like our weather winning streak may continue for most of the month. Looking ahead on the medium range forecast maps, it appears the Upper Midwest will be milder than average this month. The upper air pattern will feature a high amplitude progressive pattern with more ridges than troughs over Minnesota. That should mean stretches of three or four blissfully above average days punctuated by a cold front or two in between.

The smart money is on above average November temperatures in Minnesota.

Even the NOAA CPC 8-14 day outlook advertises above average temperatures for the region.

In the short run we should stay dry again Saturday with a high in the 60s. The NAM model is hinting at more clouds and a slight chance of a shower Sunday with a high in the 50s. Keep in mind our average high is now just 45 degrees.

Enjoy the beautiful weekend!

PH

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Saturday's weather should lift your spirits

Posted at 9:47 AM on November 6, 2009 by Mark Seeley (0 Comments)

Whatever your plans for the weekend, make sure you spend some of it outdoors on Saturday as Mother Nature delivers one of the nicest days this fall.

Hunting, golfing, having a picnic or cookout, watching football, combining the corn crop, even leaf raking should bring a smile to many faces after such a dreary October. Though temperatures are not likely to set records on Saturday in most areas they will be 15 to 20 degrees warmer than normal.

Daytime temperatures in the 60s F are somewhat rare for November 7th. For the Twin Cities this happens only about once every 8 or 9 years historically though since the new millenium we have seen a trend toward warm temperatures on this date. This will be the 5th time we have reached 60 degrees F or higher since 2000. The record high for November 7th is an old one, 72 degrees F back in 1874.

Plenty of sunshine, light winds, and modest humidity will heighten the pleasure of the day. I suspect it will be the nicest day for football seen so far this fall.

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Friday Forecast: Out on a weather limb

Posted at 6:10 AM on November 6, 2009 by Paul Huttner (1 Comments)

Twin Cities NWS graphical forecast Thursday at 11pm says 57 for a high on Friday.

Call me crazy. Call me a weather optimist. Best case scenario bias on this one. Maybe I just want a small hint of summer back. I'm out on the proverbial weather limb, and I hope it doesn't get sawed off. I may have to scrape the weather egg off my face Friday afternoon.

I think the forecast models have underestimated (possibly grossly underestimated) the magnitude of the warm air about to spill into the Twin Cities this weekend.

All week long the models have been suggesting high temperatures of about 55 to 57 degrees for Friday. These numbers were based on assuming a low deck of stratus clouds persisting all day Friday. We've had a few clouds overnight, but it's been up around 5,500 feet and there may be enough wind to mix that layer out into drier air and give us more sunshine Friday.

The local forecasts from various media and NWS as of 11pm Thursday night range from 57 to 62 on Friday.

This is probably a great range. But there is also another scenario in which the models have underestimated the warming as they sometimes do in late season, and overestimated the amount of cloud cover in a dry air mass. One result could be more sun and a higher temperature than any of those numbers by Friday afternoon as the thermal ridge moves overhead. The upstream air mass under the thermal ridge in central Nebraska Thursday was well into the 70s, but that was with some help from downslope warming. We won't get that help in Minnesota.

So here's my fun little forecast for Friday's max temp if the "high end" scenario plays out.

Twin Cities max temp for Friday: At least 65 degrees, with 70 very close by in southwest Minnesota, and not out of the question in the southwest metro. Late day surge of mild air wins the day in southern Minnesota.

Let's see how well the models handled Friday with Tom Crann on ATC Friday PM.

Enjoy!

PH

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Update: El Nino strengthens

Posted at 12:28 PM on November 5, 2009 by Paul Huttner (1 Comments)

CPC graphic shows Tropical Pacific SST's warmed rapidly the past few weeks.

An updated monthly report today from NOAA's Climate Prediction Center shows El Nino is gaining strength in the Pacific Ocean. Sea surface temperatures in the tropical Pacific rose as much as 1 degree Celsius in October. Large areas of the tropical Pacific Ocean are now +1.5 degrees Celsius above average.

The CPC forecast for this winter remains for at least a moderate strength (3-month Niño-3.4 SST index of +1.0°C or greater) El Nino. According to the CPC, the anticipated effects of this level El Nino include:

"For the contiguous United States, potential impacts include above-average precipitation for Florida, central and eastern Texas, and California, with below-average precipitation for parts of the Pacific Northwest. Above-average temperatures and below-average snowfall is most likely for the Northern Rockies, Northern Plains, and Upper Midwest, while below-average temperatures are expected for the southeastern states."

The latest CPC three month outlook for Dec-February highlights the anticipated warmth in the northern states.

The various CPC models show wide disagreement on the eventual strength of El Nino this winter. From the CPC discussion:

"There continues to be disagreement among the models on the eventual strength of El Niño, but the majority indicate that the three-month average Niño-3.4 SST index value will range between +1.0°C and +1.5°C during the Northern Hemisphere winter (Fig. 5). Consistent with the historical evolution of El Niño, a peak in SST anomalies is expected sometime during November-January. At this time, there is a high degree of uncertainty over how long this event will persist. Most of the models suggest that this event will last through March-May 2010, although the most likely outcome is that El Niño will peak at least at moderate strength (3-month Niño-3.4 SST index of +1.0°C or greater) and last through at least the Northern Hemisphere winter 2009-10."

It will be interesting to see how strong this El Nino will be as it reaches maturity in the coming months.

PH

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November warmth: A new trend?

Posted at 8:33 AM on November 5, 2009 by Paul Huttner (2 Comments)

Twin Cities NWS graphical forecast showing 60s Saturday.

Many are welcoming a change to warmer temperatures this weekend. There is a history of Indian Summer in early November in the past few years. Three of the past 4 Novembers have featured warm spells early in the month with temperatures reaching above 70 degrees in the Twin Cities at least one day.

While early November warm spells seem to be more common, there are several unusual and remarkable aspects to the warm spell this year.

It is interesting to note that the sun angle and intensity at this time in November is about equal to the first week in February. Yet temperatures will be much warmer in November even with the same amount of solar energy coming in. There are some obvious reasons why this happens.

-The ground is free of snow cover right now. That means that instead of solar energy reflecting back into space on higher albedo (more reflective) snow cover, more incoming solar energy is available to heat the lower atmosphere in November than February.

-There is still plenty of warm air to the south in late fall to be moved (advected) into the Upper Midwest.

-Overall, the atmosphere at this latitude is warmer in November than in February due to the seasonal lag (residual heat) of late summer and fall.

It is also interesting to note that while it was in the upper 20s in the Twin Cities this morning, it was in the 50s in Denver at over 5,000 feet elevation. Why is this? Denver is getting downslope flow, which warms the air mass east of the Rockies. Also, some of the air mass moving into Colorado is being transported form Arizona which saw record highs in the 90s again Wednesday.

Our warm up this weekend will also feature some remarkably warm overnight minimum temperatures. It may not drop below freezing again in the metro overnight until the middle of next week. That is remarkable for November, when our average low is now running about 29 degrees in the metro this weekend. In fact, the minimum Saturday morning may be in the mid 40s. That's our average high for this time of year.

Enjoy the warm up!

PH

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Arizona Heat Wave: Hottest November day on record

Posted at 4:16 PM on November 4, 2009 by Paul Huttner (0 Comments)

Tucson NWS forecast highs Wednesday show record level temperatures in the 90s.

We know it's hot in the Desert Southwest. It's just never been this hot in November for some in Arizona.

Several Arizona cities set record highs Tuesday, and more records are in danger today. Picacho Peak sits about half way between Tucson and Phoenix along I-10 in the Sonoran Desert. Tuesday afternoon the thermometer soared to 97 degrees. Phoenix hit 96 degrees. That's the hottest all-time November temperature on record for Picacho and ties the all-time hottest November temp in Phoenix.

Records Tuesday include:

Location High/Old Record / Year/ Notes

Phoenix Sky Harbor Airport 96°/ 94°/1931/ Ties all-time warmest November high.

Tucson International Airport 93°/91°/1931/ One degree shy of all-time warmest November high.

Organ Pipe Cactus N.M. 96°/ 92°/1997/ One degree shy of all-time warmest November high.

Picacho Peak 97°/ 91°/2001/ Broke all-time warmest November high (93°: 11/1/2008)

Bisbee-Douglas Airport 85°/ 85°/2001/ Two degrees shy of all-time November high.

So what does this have to do with Minnesota?

Some of this toasty air mass will filter over the Rockies in the coming days and may modify our air mass as warmer southwest winds kick in by Friday. I'm not sayin' we'll see records here which are in the lower 70s. I'm just sayin' that the models can sometimes underestimate the magnitude of warming when desert air masses get sucked into weather systems in the Upper Midwest.

I think we're a lock for at least 60 degrees in the metro Friday or Saturday. If enough warm air surges north, we could see 70s in southern Minnesota and even a stray 80 in South Dakota. Let's hope so!

PH

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Forecast: Warm front

Posted at 8:33 AM on November 4, 2009 by Paul Huttner (0 Comments)

European forecast model shows a very warm bubble of air for November at 5,000 feet surging into the Upper Midwest Friday.

This is going to be an interesting forecast.

A major league warm front is building in the high plains and will be pushing northeast into Minnesota by Friday. The big forecast question? Just how warm will it get?

As usual there are at least two competing model solutions to that question. One model, the NAM is more aggressive in surging the warm air into Minnesota by Friday. The NAM numbers suggest southwest Minnesota could see temperatures surge well into the 60s and even close to 70 degrees Friday afternoon. The 60s could linger into Saturday if you bet on the NAM.

The GFS is a little more conservative. GFS numbers suggest mid to upper 50s for southern Minnesota, including the Twin Cities, both Friday and Saturday. This would still be a good 10 to 15 degrees above average for early November. Our average high in the metro Saturday is 45 degrees.

The air mass poised to move this way is already plenty warm. High temperatures yesterday were well into the 60s to near 70 degrees in the lee of the Rockies.

A wild card with warm fronts any time of year can be cloud cover ahead of the front. If clouds develop Friday as the front pushes through, it may keep temperatures in check a bit. If we see full sun, even the lower November sun angle should be able to boost temps into the low 60s in southwest Minnesota Friday and Saturday.

Either way it's going to warm up around these parts in the next few days. It looks to stay mild and dry through the weekend. So the question really is; will temperatures be 10 or 20 degrees above average?

Now that's a nice forecast problem to have for early November!

Looking further ahead, it appears temperatures could stay mostly above average through November 14th.

Then the models hint at a big windy wet storm system moving in from the southwest. Too early to tell if it would be rain or snow yet, but mid-November is a pretty good time to get a wrapped up "panhandle hook" type storm moving into the Upper Midwest.

GFS forecast model hints at a strong storm approaching on about November 14th.

Stay tuned, and enjoy our Indian Summer as it unfolds this weekend.

PH

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Minnesota rain; St. Louis Flood

Posted at 6:14 PM on November 3, 2009 by Paul Huttner (1 Comments)

Here's an interesting tidbit about rare fall flooding along the Mississippi River in St. Louis.

It turns out our record October rains have been building river levels to the south and pushing them over flood stage. The Mississippi River is 3 to 4 feet AFS in St. Louis. The city's River Walk is under water. Roads are closed near the river. Flood warnings are in effect until Saturday.

The local NWS is a bit perplexed by the unusual fall flooding. Spring floods are common along the Mississippi, but fall floods are rare.

I think it was Mark Twain that said; "it takes a flood to end a drought.' The twist on this one might read, "it took ending a drought in Minnesota to cause a flood in St. Louis."

PH

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Nowcast: Metro rush hour rain

Posted at 3:34 PM on November 3, 2009 by Paul Huttner (0 Comments)

A band of rain rolls into the metro at 3:30pm today.

It's a wet PM rush today.

Radar is tracking a narrow band of rain sliding through the metro just in time for PM drive. Expect wet streets and wipers on medium as you're heading out this afternoon and early evening.

A few wet snowflakes may mix in on the back side of the rain band, but it looks like temperatures are warm enough for mostly rain. The rain is moving through pretty quickly. It should last about 1 to 2 hours in any one spot.

PH

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Did the Chinese make it snow?

Posted at 8:24 AM on November 3, 2009 by Paul Huttner (0 Comments)

NOAA MODIS satellite image shows snow cover plume in Mongolia and China Monday.

Meteorologists from the Chinese Weather Modification office say they made it snow in Beijing last weekend. Several inches of snow fell in the Chinese capital. It was the earliest snow in a decade for Beijing.

Reports from the BBC indicate the team sprayed 186 doses of silver iodide into the clouds west of Beijing to enhance rainfall for the drought stricken wheat crop. The subsequent heavy wet snow led to the success claims at weather modification.

The big question is, how do we know if they're right? The effectiveness of seeding clouds is questioned by many scientists. There is no good way to verify the efficacy of enhanced precipitation through weather modification. How much snow would have fallen without seeding the clouds?

If you look at the satellite image above you can see that the snowfall plume stretch back over 1,000 miles to the northwest in Mongolia. It is difficult to believe that weather modification attempts near Beijing cause snow to fall hundreds of miles to the northwest. Obviously there was already a massive snow system in progress long before it reached Beijing.

Sort of a Mongolian Clipper, if you will.

Weather modification remains an area of study in many locations in the USA. There are active programs in North Dakota and Nevada.

Stay tuned.

PH

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