Monday, November 30, 2009

Thoughts Ahead of a Couple More Snow Threats

There are yet MORE snow threats to track, one of which is out 11 days into the future so we won't spend a whole lot of time there.

The first one is Thursday into Friday. The setup has a low tracking through the Ohio Valley Wednesday into Thursday. At this time I am calling for a track from Louisville, through Cincinnati, then into Central Ohio. This would bring rain into the area Wednesday afternoon, which should mix with then change over to snow on Thursday morning. Then, an upper level trough should settle in Thursday afternoon. That would bring a northwesterly fetch and continued snow showers with a quick disturbance to enhance the action on Friday morning before tapering.

At this point in time, I DO NOT see major accumulation with this. Maybe 1" on grassy surfaces, nothing should stick to roads. So, your commutes to and from work Thursday, as well as morning drive on Friday, should be okay barring a flash freeze (which could happen).

Regardless, this sets the stage for at least one more system Sunday into Monday which again should be rain to a quick inch of backside snows - and then we've got the cold air in place and right now the long range models have an idea of a storm sliding up to our east on the 10th which would bring potentially the first 2"+ snow to our area. Too early right now to even speculate, but with the cold air in place indications are that it WOULD be all snow. Stay tuned...

NOTE: Per John Gumm at WKRC-TV 12/Cincinnati, the 12z models look "horrible" for snow, with the North American Model showing nothing at all snow wise. Stay tuned...we'll analyze that output later today.

Tuesday, November 24, 2009

Checking on the Three Storm Threats.

Good morning folks,

We're two days into the short week - and things aren't looking as interesting for next Tuesday as previously thought - but still could see our first accumulating snow.

Let's back up though and deal with the Thanksgiving storm first - which should begin to impact our area tonight but more so tomorrow.

Most models are coming to agreement with the main feature for tonight - a shortwave that sweeps through our area sometime tonight should bring about 40-50 percent coverage of rain to our area. The best chance is NORTH of Cincinnati and Dayton - but even from Dayton south has a good chance. As I said probably 40-50 percent coverage at any time tonight. Leftover rainfall could be a problem tomorrow afternoon - but I don't see issues other than wet roads for Thanksgiving travelers with this part of the storm.

The true main event comes tomorrow night through Friday. There will be a second shortwave with an associated cold front on Thanksgiving, and temperature profiles at the start are favorable for a cold rain. So for your Thanksgiving dinner plans or those who have short distance travel plans, keep in mind roads will be wet. Then, behind the front temperatures plummet into the low 30s or even upper 20s and temperature profiles suggest the rain will mix with then change over to snow showers for Thanksgiving night into Friday morning. We then dry out Friday afternoon but it remains cold with highs probably barely cracking 40. Saturday, the NWS wants to send temperatures into the upper 40s but I'm going to pull back just a bit and suggest middle 40s. Same for Sunday - I'm holding off the 50 degree temps until Monday so upper 40s looks okay there.

Then the next event comes on Monday. Right now, the 0Z GFS wants to bring the low over Cincinnati and this results in rain with a changeover to snow and maybe a few inches on the backside of the low. This seems as good a solution as any, but I am not going to be pinned down right now on track. This has 6 days to change as it would begin to affect the Greater Cincinnati area on Monday night.

There are signs that the storm behind THAT, around December 6th, could be game on for a really good snowfall - but that is even FURTHER out and so I will just mention the possibility.

Regardless of what these storms do next week, the middle of the month is GAME ON for cold, arctic air as it looks right now. Each storm over these next 14 days brings colder and colder air south across the middle of the US and I think the 12/6 storm would likely be "the big one" I spoke of in my winter outlook earlier this month.

Bottom line: Rain the next few days, changing to snow on Thanksgiving night then a rain to snow scenario (as it looks right now) next Monday-Tuesday, then a bigger snow possible around 12/6, even as we get colder and colder.

Have a great Tuesday everyone,

Jeremy Moses

Monday, November 23, 2009

Looking Ahead: Snow Threat More Pronounced for Thanksgiving, Black Friday!

Good morning ladies and gentlemen,

We're going to start your short workweek on the chilly side, and with a few rain showers in the southeastern counties of the Cincy Tri-State. In particular, Brown, Adams, Highland and Scioto counties in Ohio and Bracken, Mason, Lewis and Robertson counties in Northern Kentucky could see a couple light showers early this morning with a small disturbance. It should not be a big deal, however. Anybody in the Tri-State could actually see a few light showers anytime on Monday, as we struggle to reach 55.

But - and you had to know there'd be a but - there's a more sustained rain threat as we go into Tuesday night through Thanksgiving. A cold front will sweep into, then through the Greater Cincinnati area during that time period. While it won't be carrying any significant instability (and thus, no thunderstorm threat), it WILL have plenty of moisture to work with. As such, I look for rain to start late Tuesday night or early Wednesday morning, and continue through much of Thursday. Generally from Monday through Wednesday, lows will be between 35 and 45 and highs between 50 and 55.

Then it gets tricky. While I expect precipitation to continue...models are literally all over the place with type and the speed of a closed low that will drop into the northern Great Lakes on Thursday night and Friday. The Global Forecast Service Model wants to keep temperatures warm enough through most of the atmosphere to support all rain. The European upper air model, however, wants to bring enough cold air into the area for a rain/snow mix, and I'm inclined to agree for Thursday late day and Thursday evening. However...I do think all layers cool off enough overnight on Thanksgiving night and through the first half of Friday to support a changeover to all snow for the area, even south of the Ohio River. Friday's highs won't even get past the lower 40s (I am calling for 43) after a raw Thanksgiving with highs only around 46. It should be noted, however, that enough of the ground is still above freezing to not really worry about accumulating snowfall for Thursday night and Friday. Then we dry out Saturday, and another system swings in Sunday with a few more rain showers. We'll be below normal on Saturday as well with highs around 44, and back near normal Sunday with 48.

BUT...our focus turns to the models again for NEXT week. And wouldn't you know it - the long range models actually want to bring in the snow threat I talked about previously for around the 5th or 6th of December - AND are introducing a NEW threat for next Tuesday! The 12/1 storm needs to be monitored closely - as it looks BIG!

So to sum up the next 7 days:

== Near normal temperatures today through Wednesday
== Rainy Tuesday night through Thursday
== First snow of the season looks LIKELY Thursday night and Friday Morning
== BELOW normal temps from Thursday through Saturday, recovering to near normal on Sunday
== WATCH OUT week of 11/30-12/6 - TWO significant winter weather threats??

Saturday, November 21, 2009

Turning Colder - SNOW on Thanksgiving Night???

We're enjoying some nice weather this weekend - after cold starts this morning and Sunday morning.

As of 5:00 AM, temperatures ranged from 30 in Hamilton, OH to 36 at the Cincinnati/NKY International Airport to 43 in Jackson, Kentucky. 30-36 is the general range around town right now (the center of Cincinnati, however, may be in the upper 30s or lower 40s).

We'll remain sunny today as fog that is currently hanging over the Tri-State burns off by 10 AM. Watch out north of town if you're traveling this morning, however...some of this fog is actually FREEZING FOG and will freeze on bridges and overpasses!

As we go through the day, we'll be sunny with highs around 55. Tonight, watch for patchy fog to develop again and again there may be problems with freezing fog in valleys north of downtown if temperatures dip low enough. For the rest, there might be some frost tomorrow morning.

Sunday looks great as well with highs approaching 60.

The next chance of rain slides in Monday and Tuesday with a 30 percent chance of rain both days and highs in the mid to upper 50s.

Then...here comes the first winter blast.

The models indicate some colder air developing and sinking southbound into the Tri-State on Wednesday. This is the catalyst for changes in our pattern. By Thanksgiving Day, another system will be moving in. Right now, it is too early to say with total certainty what precipitation type the Tri-State will see. But...at least one model wants to put something of a mix of rain, snow and maybe ice pellets into the Tri-State Thanksgiving Night.

Here's how the GFS depicts Sea Level Pressure, the past 6 hours of precipitation, and 850 mb (or 5,000 feet) temps at 144 hours (or 7 PM Thanksgiving Evening) courtesy of NCEP as of the 7 PM model run. (With these, you can click the small version to receive the full resolution version) Note where the 0C line is at 5000 feet:



Here's the model run for those same parameters at 150 hours (Again, click for hi resolution).



Oh and here are the 2 meter temps and 10 meter winds with precip for those same two time periods also courtesy NCEP (As before, you can click these to get full resolution):





Those 2m temps wouldn't cause too much concern - but, if we're cold/cool on Wednesday, this could change.

IF the snowfall comes to pass, it won't amount to any significant accumulation. Could that change, sure...but it looks like my prediction of a significant snow near Thanksgiving could bust. Again - still too early to say, so I could be eating crow on Black Friday instead of leftover turkey...but hey, I've given it a good try, haven't I???

The pattern begins to change...and there's chances for signficant snow past that, but as they are so far out that you can't rely on the models to interpret them I'll leave that out for now. Watch out though if anything starts showing a good storm for on or near December 3-4, especially if the possibility shows up after Thanksgiving! A recent model run teased that possibility - so I will be watching to see if it brings this back!

Where else will you get this kind of analysis for FREE? Not at one of the "other" independent sources in town...they charge for this.

Saturday, November 14, 2009

Looking to the week ahead...

We have enjoyed yet another nice day across the Tri-State! It was beautiful, with highs around 66 (as of 4 PM) at the Cincinnati/N KY International Airport, as well as at Dayton and Columbus.

Well, I hope you enjoyed that - because we won't reach that mark again for at least the next week after tomorrow.

Our weather pattern looks to change in the next 48 hours, as a cool front comes into the area tomorrow evening. Before that...one more day of 60 degree weather tomorrow. I'm calling for a high of 62, but some locations will get to around 66 or 67 one more time, mainly south and east. We'll be partly sunny most of the day, with clouds moving in and becoming more widespread late.

As the front moves into the area on Sunday night, we'll turn cloudy. But...one change from this morning - the front looks to come in dry. There's just not enough lift or forcing for any rain - consequently even the 20 percent chance of rain is out of the forecast, but I can't rule out an isolated shower west/northwest of town in the early evening. That front could stall along the river on Monday - so I'm hesitant to make a temperature forecast at this time especially as models want to put KY into the warm sector. For now, will go with a high of 60, but reserve my right to change it on Sunday.

Now...there's some uncertainty beyond this point, so follow me here. By Tuesday, a closed low somewhere near St. Louis will begin moving north. Because it's closed off from the jet stream, it won't move fast. That low starts bringing moisture into our area on Wednesday, so I'm inclined to introduce a 30 percent chance of rain, and by Thursday rain seems to be a 50/50 shot, then Friday is the best threat of rain with a front finally forcing its way through the area. Saturday should finally see the rain end and drying moving in.

Bottom line, an unsettled, cooler pattern looks to take hold - so enjoy the 66 and sunshine you had today...

Thursday, November 12, 2009

November Nor'easter!!!

What a wild night it is on the east coast!!!

Yours truly has a friend named Trisha who now lives down in Virginia Beach, and from what we're hearing, it rained the entire day out there on Wednesday.

Unfortunately, it looks like Trisha and everyone else from New Jersey to the Carolinas will not be catching a break today.

Just for VA Beach alone, there's a Coastal Flood Warning, High Wind Warning, Flood Watch, and High Surf Advisory, ALL IN EFFECT until Friday night or Saturday morning! It's the same story in North Carolina, the Tidewater of Virginia, and the Delmarva peninsula as well as New Jersey.

For those areas, they won't get out of this mess until Friday...and by then we could very well have millions of dollars of damage done all along the east coast between coastal and river flooding ALONE, not to mention incidental losses from the high winds of 40-65 mph (e.g., spoiled food at grocery stores and schools, trees on buildings, things like that).

The nor'easter is not moving very fast...consequently, this could be a historic event for the areas mentioned. I don't see the storm moving away from the coast or impacts lessening until Saturday.

For the Tri-State...there remains not very much to talk about. We look to remain dry through about Monday night - a 50 percent chance of rain arrives for Tuesday.

Forecast: Today: Sunny, relatively pleasant for Nov. 12. High: 58.
Tonight: Clear, chilly. Low: 39.
Friday: Sunny, a tad warmer. High: 61.

Currently at 4:00 AM 11/12/09: Fair, 38 degrees. Wind chill is 32

Sunday, November 8, 2009

Talking Ida and a Cooldown

Briefly, before I get to the meat of my discussion on Hurricane Ida, let's briefly talk Tri-State Weather... it looks like a decent day for tomorrow. A cold front comes through Tuesday and knocks us back about 15 degrees, with highs in the 50s from Wednesday on. That front might actually be mostly dry - I don't see a lot of moisture in the air, much less other dynamics we need for widespread rain.

Now, to Ida.

Hurricane Ida at this hour is located 445 miles south-southeast of the mouth of the Mississippi River. Maximum winds are at 105 miles an hour, with gusts to CAT 3 strength. However, we don't expect it to become a CAT 3. In fact, it may be weakening now - pressure is 979 millibars, up from 976 at 4 PM.

Ida should be running into colder waters in the Gulf of Mexico tonight and tomorrow. Along with this, westerly shear will start to tear the convection apart. Sometime on Tuesday morning, then, Ida will merge with a cold front (in fact the same one that will impact us) and become extratropical, or a cold-core system. Before then, Ida will steadily weaken from tonight on.

As to the track - the front will also steer the system. It will move north, then northeast. Landfall will most likely be on the Florida Panhandle. However, there's still a wide area that could be impacted - anybody from southern Louisiana to Florida should be watching this storm. Winds at landfall will still be upper-end tropical storm force to at worst lower-end CAT 1 hurricane force. Until it landfalls, we can't be sure what kind of damage we'll see. But, I do not think it's a huge deal.

I will be following this closely tonight and tomorrow. Stay tuned...

Tuesday, November 3, 2009

Tuesday Evening Forecast - Not Much Change

Good evening everyone,

We're still dealing with the reinforcing shot of cold air that came through last night. We only reached 53 so far (as of 4 PM), and now we're going to start dropping.

By morning, our low of 32 looks easily attained, as we remain clear. There won't be any cloud cover until the morning hours tomorrow, when the next disturbance rotates through the tri-state. With the limited amount of moisture in the air, there's just no chance of steady rainfall in our forecast tomorrow...maybe a sprinkle here or there.

Our temperatures remain cool all the way from tomorrow through Saturday, remaining near or just below normal.

~Jeremy Moses

Winter Outlook 09! (Re-worded 11/3/09)

WINTER OUTLOOK 2009-2010
By Jeremy Moses

It is time for me to publish another Winter Outlook. It is my second year dabbling into this kind of forecasting, so we'll see how it stacks up.

The first thing to do at this point is to look at how October shook out as it pertains to averages. As you'll see, we were above normal in precipitation:



...but below normal with regards to temperatures:



Indeed, the ONLY areas above normal in temperatures were the Gulf Coast and the Southwest!

Soil moisture is another real key to what happens this winter, also - in fact, it tells us the same thing as the previous maps. Much of the eastern US was above the average, and in fact, as of last week, it showed this:



Snow Cover and Solar Activity

Snow cover has been expanding rapidly across the Arctic, and the sea ice is building up there as well. This map illustrates the latest information.



By comparison, where are we normally this time of year?



As you can see, we're mostly near normal. Actually, western Canada seems to be the exception - but, with warm and dry having been the rule there, that's expected. Look for this to increase over the next couple or three weeks.

Solar action has been minimum. I know I have never seen it this quiet solar wise in my 24 years of life. This is expected to continue and the current solar cycle does not even look like it will peak until 2013 or 2014

EL NINO

El Nino is, as usual, a major topic at this time of year. Take a look at these Sea
Surface Temperatures, as recorded TODAY...



As you can see, we've got SST's of 22-24 degrees Celsius just off the west coast of South America. That spells trouble - El Nino style trouble.

I, like many forecasters, am anticipating a weak El Nino this year...although we might start winter with a moderate one. Take a look at this map, showing what usually happens in a weak El Nino year temperature wise. (Analog Years are 1957-58, 1965-66, 1977-78, 1987-88, 1992-93, 1994-95, and 2002-03.)



Due to recent warming and a POSSIBLE westerly wind burst in November (I'll need to see what I can find to support such - but just know it's possible), El Nino could, and should, reach moderate status fairly soon, as I have previously noted. I don't think it gets any stronger than that. A strong El Nino would not bode as well for snow lovers.

All the ENSO (El Nino Southern Oscillation) models (save a couple, but I think we can throw those out) suggest we'll see a peak in the first half of the winter.



Again - as there are currently, and I stress currently, no indications of a strong El Nino in the forecast, I really don't expect one. So any solution of a dry and mild winter could be thrown out as of right now. Indeed, there's more evidence suggesting colder and stormier than there is warmer and drier.

QBO (quasi-biennial oscillation)

Negative QBO suggests high latitude blocking in the Northern Hemisphere. The QBO index has been in the negative teens for several months, and I am expecting this to continue. So, a negative phase QBO = blocking = West Ridge/East Trough.

NAO (North Atlantic Oscillation)

The NAO was negative a good part of October. As we head through winter, look for changes as usual. However...El Nino tends to impact the NAO. As El Nino weakens, I look for the NAO to completely bottom out - when it does, WATCH OUT...that's when the cold air will flow!

PNA (Pacific-North American Teleconnection Pattern)

When positive, the PNA index (just like the QBO in the opposite phase) supports ridging out west and troughing to the east. That should be the case this winter...I'm thinking we are going to be positive for a good part of the second half of winter, especially in the new year. That, just like the NAO being negative, will let the cold air flow south.

PDO (Pacific Decadal Oscillation)

I am anticipating the PDO to go cool. Whenever we're in a cold phase of the PDO during a weak El Nino, record cold usually results in the Eastern US. It has been rising toward neutral, and even weakly positive in September. However, I expect it to cool and go weakly negative. If a -PDO and -NAO coincide at ANY time this winter - LOOK OUT - especially in the northeast!!

Storm Track

For this winter, I am anticipating the storm track to shift over several months. For most of November, I anticipate the storm track staying north and west of the Ohio Valley. The below map will illustrate this, along with the paragraphs to follow.



By the middle of this month, I am anticipating our stormtrack to shift. That shift places us in the sweet spot around or just after Thanksgiving...and I think our first significant snow could happen right around that time. It will stay that way until the end of December...then a shift to the east coast will take us out of the Apps Runner threat, shifting the heavy snow with it - but we'll be in the cold air by that point. I don't expect another heavy snow threat after the end of December until the beginning of March. More on this below.

So Where Does That Leave Cincinnati and the Ohio Valley??

Here's a monthly breakdown, from November through March.

November - I am anticipating the current pattern to continue through around November 10. After that, the storm track shifts southeast and by the end of the month, is established along the west slope of the Appalachians. At first, the storm track will mean more snow to our northwest, which should allow the colder air to establish itself very well. If I needed to hazard a guess as to first accumulating snow, I will say on or around November 26th. Our last gasp at 70 is likely between the 12th and 18th.

December - The pattern continues to be favorable for snow for Cincinnati. The Pacific Jet should keep the storminess going. The Southeast Ridge could potentially be a problem, we don't know for sure - this tends to wreak all kinds of monstrous havoc with precip types. HOWEVER...I don't anticipate it being a big problem for the area for this December... and so consequently, this should be a good month for snow lovers. If anything, we've got our best shot at a HUGE storm, right here...likely midmonth, just before the track shifts even further south and east. There may be a period or two of milder air, particularly early in the month (50s as opposed to 30s) but it won't get to 70 - I can guarantee you this.

January - I actually look for the stormtrack to be further southeast than we'd like from 1/5 onward, it's going to shift to the east side of the Apps... that means less significant snowfall potential - but the cold air is well established by this time, and I do think we are going to see a lot of clipper type systems that run through quickly but also drop a couple or three inches of snow while they do. That should be enough to put us near average for the month snow wise. This is when the NAO will begin tanking.

February - I expect February to be much the same as January. The storm track transitions to an East Coast track which is still less favorable for big synoptic snows. Even so, the trend favors more clipper systems = another near average month. Also, if we're going to see record cold temperatures - February will be the time, most likely mid-month.

March - We have a pretty good chance at a good size snowfall early in the month. In fact, it's our second chance at a monster storm a la the Blizzard of '08. Am I saying one WILL happen like that? Nope - but it's our second best shot at something close. At that point, however, the transition to spring will begin so milder air will start to come in, leading to less and less snow chances. Eventually, the end of this month should bring the last breath of cold air - and by this time, highs could be in the 50s.

So how much snow will we see? The below map is a pretty good idea.



So, that's my look at winter. I do have the same thoughts as another forecaster, and his thoughts can be read at this link. However, the wording is intended to be my own.

Dry Week Ahead...Mostly At Least.

What a weekend we had here in the Tri-State!

It was 80 degrees on Friday. By Sunday morning, it was FIFTY degrees colder! What a change! A change that, I'm sure, is wreaking havoc with people's bodies (it is yours truly's at the moment as I type this).

But, there's no more large, 50 degree temperature swings in the forecast, at least not like that, for a while...and we probably won't see 80 again this year.

We're going to be set up in a progressive upper air pattern this week. Anything that comes through, is going to be moving very quickly. The thing is...most of what systems do move through, will be dry.

I really do not see any rain in our forecast in Cincinnati this week. As a matter of fact, the fronts coming through tonight as well as Wednesday night, will be dry. So, increases in clouds will occur...but don't expect any rain as there's just not going to be enough 1) upper air support and 2) significant moisture.

Temperatures will stay below average the rest of the week...and then a modest increase over the weekend into next week.

So, in short: No rain, cool temperatures this week...still no rain, and warmer temperatures over the weekend into early next week.

Enjoy your week!