Medium Range Discussion Summer 2012

[donsutherland1]

With summer approaching, I'm starting a Summer 2012 thread. My summer thoughts will be posted toward the end of the week. This evening, I'll post my thoughts for the first week in June.

June 1-7, 2012 Thoughts:

The pattern that appears likely to kick off the first week of Summer 2012 is likely to produce widespread warmth across North America. Although that pattern has typically resulted in cool anomalies across much of Canada and part of the U.S., the lack of cool anomalies in the Arctic region will result in those areas also seeing mainly warm anomalies.

The charts below are as follows:

Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of -0.2°C to +0.5°C, a PNA of -1.50 to 0.00, and an AO of +0.25 to +1.50 for North America.

Right: NAEFS for the May 30-June 5, 2012 timeframe

Overall, I expect most of North America to see warmer than normal conditions for the first week of June. Portions of California to British Columbia could see cool anomalies. Whether or not the warmth of the first week in June may indicate a warm summer remains to be seen. However, the picture is decidedly mixed with a few of the most recent analogs having turned toward the warmer side, especially for the first half of summer. The most recent analogs also continue to suggest a quieter than normal Atlantic hurricane season despite the early formation of Alberto.

Finally, it should be noted that verifications for a number of the May forecasts will be forthcoming later this week, as well.

[uncle W]

good luck Don...I think the above normal trend will continue into June...How far into June is the question...I'd love to see a 1965 type summer with some very cool days but I fear it will turn out like 1991 or 2002...

[weatherwiz]

Great post, Don. in a pattern such as the image on the left that could lead to increased potential in severe weather chances for much of the northern Plains/upper Mid-west, Great Lakes, and the Northeast.

[The_Global_Warmer]

This is part of the reason more heat waves are happening. The albedo loss right now is big time compared to the average year vs the last 46. that is a large area of Eurasia without snow cover to reflect the solar energy back at a .60 melting snow, to .85 dry snow. vs the land of .12 to .30. Tremendous change.

[easternsnowman]

If the above normal trend continues it will become quite obvious that we can no longer consider the 1981-2010 averages to be normal and I continue to believe that 2 or 3 degees above that is the true normal for these times.

[donsutherland1]

June 2012 Forecast:

Although past transitions to possible El Niño conditions have witnessed a chilly summer, it appears that the current transition will witness at least the first month of summer turning out warmer than normal across much of North America.

Key Assumptions:

• Neutral ENSO conditions are likely to prevail through much or all of June

• The AO will likely be near neutral (with variability in negative and positive ranges)

• The PNA will likely be predominantly positive (but generally < +1)

The top analog was 1969. Both 1953 and 2009 were close behind.

The charts on which my June idea is based are:

Left: Composite temperature anomalies based on ENSO/Teleconnection Analogs.

Right: Observed Decadal Temperature Change for June

Some of the greatest warm anomalies in the East occurred during the 6/20-30 timeframe, especially in 1953 and 1969. The leading analogs do not clarify the ENSO situation going foward, but they maintain the theme that odds lean toward the develop of an El Niño. 1953 saw neutral ENSO conditions. 1969 and 2009 witnessed the onset of El Niño conditions.

Based on the combination of the composite teleconnection analogs, observed notable warmth in the Arctic region, and the observed decadal temperature changes, my thoughts for June are as follows:

Much of North America will likely be warmer than normal. A portion of northern Canada could be near to somewhat above normal. Part of the West Coast, probably somewhere in California to perhaps the Pacific Northwest could be cooler than normal.

[Met1985]

June 2012 Forecast:

Although past transitions to possible El Niño conditions have witnessed a chilly summer, it appears that the current transition will witness at least the first month of summer turning out warmer than normal across much of North America.

Key Assumptions:

• Neutral ENSO conditions are likely to prevail through much or all of June

• The AO will likely be near neutral (with variability in negative and positive ranges)

• The PNA will likely be predominantly positive (but generally < +1)

The top analog was 1969. Both 1953 and 2009 were close behind.

The charts on which my June idea is based are:

Left: Composite temperature anomalies based on ENSO/Teleconnection Analogs.

Right: Observed Decadal Temperature Change for June

Some of the greatest warm anomalies in the East occurred during the 6/20-30 timeframe, especially in 1953 and 1969. The leading analogs do not clarify the ENSO situation going foward, but they maintain the theme that odds lean toward the develop of an El Niño. 1953 saw neutral ENSO conditions. 1969 and 2009 witnessed the onset of El Niño conditions.

Based on the combination of the composite teleconnection analogs, observed notable warmth in the Arctic region, and the observed decadal temperature changes, my thoughts for June are as follows:

Much of North America will likely be warmer than normal. A portion of northern Canada could be near to somewhat above normal. Part of the West Coast, probably somewhere in California to perhaps the Pacific Northwest could be cooler than normal.

Thanks Don for all the work. This seems like the new norm with the temps. Just say above average and you will be ok.

[donsutherland1]

Summer 2012 Thoughts:

Recent analogs have continued to suggest that odds somewhat favor the development of an El Niño during the summer. The fresh burst of westerlies out in the Pacific that has sent the SOI to -27 offers another hint, as El Niño events are typically preceded by bursts of westerlies that damp the easterly trade winds. However, given recent SSTAs, it is likely that the transition to El Niño will probably be somewhat discontinuous, with warming SSTAs followed by some cooling and then renewed warming.

The key assumptions for my summer thoughts are:

• The onset of El Niño conditions, possibly during July or August

• Possible return of PDO+ conditions

• A continuation of general warmth in the Arctic region

Typically, such a scenario would lead one to assume that the Great Lakes region and New England and perhaps a larger portion of North America would wind up cooler than normal. The persistence of the 2009 analog (ranked #2 for my June thoughts and narrowly #1 for summer with 1991 a close second) would also argue for a lot of cool anomalies. However, that exceptional anomaly is largely offset by the others, which account for more than 60% of the overall summer anomaly.

Afterward, there is the modeling. The CFSv2 has a large area of North America forecast to be above normal. Some of the warmest anomalies on that model show up in northern Canada, the Great Lakes region, and the Plains States. Likewise, the European Model has a generally warm forecast for a large section of North America.

Summer decadal trends have much of the U.S. and eastern Canada warmer than normal. Portions of northern Canada are cooler than normal.

Then, there is the persistent warmth in the Arctic region. If the source region of cool air masses remains anomalously warm, patterns that normally would produce chilly conditions in Canada and the U.S. would wind up less cool. Hence, such patterns would overperform on the warm side.

Recent trends in the analogs and modeling (e.g., CFSv2) have been toward warmer ideas. A warmer outcome than what I expect is not out of the realm of possibility. I didn't embrace an even warmer scenario, because I am assuming that the El Niño will develop and that the resulting pattern, especially during the latter part of summer, could be sufficient to blunt the warmth in the Great Lakes area and New England (for the 3-month averages). Nevertheless, even those areas could experience some much above normal readings, possibly during the first half of summer.

Taking into consideration all this data, my summer thoughts are as follows:

West Coast (except for the Pacific Northwest) would wind up somewhat cooler than normal. The Pacific Northwest will likely be near to somewhat warmer than normal. The Great Lakes region (U.S. States and Ontario), Northern Plains and New England would likely wind up near normal with some areas of cool anomalies. The rest of the U.S. would wind up warmer than normal. The warmest anomalies would likely extend from Texas northward into the Central Plains and then eastward into the Western Gulf States. Northern Canada and much of eastern Canada, along with central Manitoba northward and central Saskatchewan northward would likely be warmer than normal. Alaska would likely have a warm summer. The rest of Canada could be near normal.

[donsutherland1]

June 8-15, 2012 Thoughts:

The second week of June could be shaping up as the coolest week relative to normal across parts of North America. Both the forecast MJO and the teleconnection analogs suggest that an area running from the Great Lakes region into central Canada could witness cool anomalies. Most of the warmth would be confined to the western half of the U.S.

However, if one takes a look at some of the analogs coming up, one could be seeing a signal for the month to end on a hot note. Among the analogs showing up for the second week of June are 1953, 1966, 1969, and 1977. All four of those years witnessed excessive heat in the closing 7-10 days of June. Moreover, 1969 was the leading June analog.

The charts below are as follows:

Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of -0.2°C to +0.5°C, a PNA of 0.00 to +1.00, and an AO of -0.50 to +0.50 for North America.

Right: MJO of Phases 5-6 (Amplitude 0.5 to 2.0) during Neutral ENSO conditions in June

All said, my thoughts are as follows:

- Great Lakes region to the James Bay area of Canada: Generally cooler than normal readings.

- Eastern third of the U.S. and Quebec eastward in Canada: Near normal to somewhat above normal readings

- Western half of the U.S., except for the Great Lakes region/western third of Canada/Alaska: Generally warmer than normal

[Ottawa Blizzard]

Summer 2012 Thoughts:

Recent analogs have continued to suggest that odds somewhat favor the development of an El Niño during the summer. The fresh burst of westerlies out in the Pacific that has sent the SOI to -27 offers another hint, as El Niño events are typically preceded by bursts of westerlies that damp the easterly trade winds. However, given recent SSTAs, it is likely that the transition to El Niño will probably be somewhat discontinuous, with warming SSTAs followed by some cooling and then renewed warming.

The key assumptions for my summer thoughts are:

• The onset of El Niño conditions, possibly during July or August

• Possible return of PDO+ conditions

• A continuation of general warmth in the Arctic region

Typically, such a scenario would lead one to assume that the Great Lakes region and New England and perhaps a larger portion of North America would wind up cooler than normal. The persistence of the 2009 analog (ranked #2 for my June thoughts and narrowly #1 for summer with 1991 a close second) would also argue for a lot of cool anomalies. However, that exceptional anomaly is largely offset by the others, which account for more than 60% of the overall summer anomaly.

Afterward, there is the modeling. The CFSv2 has a large area of North America forecast to be above normal. Some of the warmest anomalies on that model show up in northern Canada, the Great Lakes region, and the Plains States. Likewise, the European Model has a generally warm forecast for a large section of North America.

Summer decadal trends have much of the U.S. and eastern Canada warmer than normal. Portions of northern Canada are cooler than normal.

Then, there is the persistent warmth in the Arctic region. If the source region of cool air masses remains anomalously warm, patterns that normally would produce chilly conditions in Canada and the U.S. would wind up less cool. Hence, such patterns would overperform on the warm side.

Recent trends in the analogs and modeling (e.g., CFSv2) have been toward warmer ideas. A warmer outcome than what I expect is not out of the realm of possibility. I didn't embrace an even warmer scenario, because I am assuming that the El Niño will develop and that the resulting pattern, especially during the latter part of summer, could be sufficient to blunt the warmth in the Great Lakes area and New England (for the 3-month averages). Nevertheless, even those areas could experience some much above normal readings, possibly during the first half of summer.

Taking into consideration all this data, my summer thoughts are as follows:

West Coast (except for the Pacific Northwest) would wind up somewhat cooler than normal. The Pacific Northwest will likely be near to somewhat warmer than normal. The Great Lakes region (U.S. States and Ontario), Northern Plains and New England would likely wind up near normal with some areas of cool anomalies. The rest of the U.S. would wind up warmer than normal. The warmest anomalies would likely extend from Texas northward into the Central Plains and then eastward into the Western Gulf States. Northern Canada and much of eastern Canada, along with central Manitoba northward and central Saskatchewan northward would likely be warmer than normal. Alaska would likely have a warm summer. The rest of Canada could be near normal.

Very interesting Don. JB has been tweeting since the early spring that an El Nino could develop and that summer could average normal to below normal in the east. He tweeted today that June will average normal to below in the Great lakes region. It will be interesting to see how that turns out. It's interesting how cool summers seem t oshow their face in June. Take 1816 and 1992 for example. I well remember the cold front of May 24-25, 1992 as I had received a new baseball glove for my birthday and found it difficult to break into given the weather was abnormally cold the last week of May that year. Also, New England saw snow the first week of June 1816. Now, I'm not saying we're going to get anything like that - there's been no massive tropical volcanic eruption for one thing!

[CoastalWx]

I agree Don about the first half of June. I'm a little concerned or coastal areas of New England as onshore flow could much things up..especially next week. My guess BOS throws up - departures during this time. That's a good -NAO block right now.

[Harry]

Summer 2012 Thoughts:

Recent analogs have continued to suggest that odds somewhat favor the development of an El Niño during the summer. The fresh burst of westerlies out in the Pacific that has sent the SOI to -27 offers another hint, as El Niño events are typically preceded by bursts of westerlies that damp the easterly trade winds. However, given recent SSTAs, it is likely that the transition to El Niño will probably be somewhat discontinuous, with warming SSTAs followed by some cooling and then renewed warming.

The key assumptions for my summer thoughts are:

• The onset of El Niño conditions, possibly during July or August

• Possible return of PDO+ conditions

• A continuation of general warmth in the Arctic region

Typically, such a scenario would lead one to assume that the Great Lakes region and New England and perhaps a larger portion of North America would wind up cooler than normal. The persistence of the 2009 analog (ranked #2 for my June thoughts and narrowly #1 for summer with 1991 a close second) would also argue for a lot of cool anomalies. However, that exceptional anomaly is largely offset by the others, which account for more than 60% of the overall summer anomaly.

Afterward, there is the modeling. The CFSv2 has a large area of North America forecast to be above normal. Some of the warmest anomalies on that model show up in northern Canada, the Great Lakes region, and the Plains States. Likewise, the European Model has a generally warm forecast for a large section of North America.

Summer decadal trends have much of the U.S. and eastern Canada warmer than normal. Portions of northern Canada are cooler than normal.

Then, there is the persistent warmth in the Arctic region. If the source region of cool air masses remains anomalously warm, patterns that normally would produce chilly conditions in Canada and the U.S. would wind up less cool. Hence, such patterns would overperform on the warm side.

Recent trends in the analogs and modeling (e.g., CFSv2) have been toward warmer ideas. A warmer outcome than what I expect is not out of the realm of possibility. I didn't embrace an even warmer scenario, because I am assuming that the El Niño will develop and that the resulting pattern, especially during the latter part of summer, could be sufficient to blunt the warmth in the Great Lakes area and New England (for the 3-month averages). Nevertheless, even those areas could experience some much above normal readings, possibly during the first half of summer.

Taking into consideration all this data, my summer thoughts are as follows:

West Coast (except for the Pacific Northwest) would wind up somewhat cooler than normal. The Pacific Northwest will likely be near to somewhat warmer than normal. The Great Lakes region (U.S. States and Ontario), Northern Plains and New England would likely wind up near normal with some areas of cool anomalies. The rest of the U.S. would wind up warmer than normal. The warmest anomalies would likely extend from Texas northward into the Central Plains and then eastward into the Western Gulf States. Northern Canada and much of eastern Canada, along with central Manitoba northward and central Saskatchewan northward would likely be warmer than normal. Alaska would likely have a warm summer. The rest of Canada could be near normal.

All it takes is a parade of these cut off systems like the one later this week to do the deed and thus send temps into the -negative side regardless of how much above normal temps are across the Arctic. Was either 2008 or 2009 that had that sort of thing?

But yeah i strongly believe June will end up on the -negative side in this region and NE.

[donsutherland1]

Very interesting Don. JB has been tweeting since the early spring that an El Nino could develop and that summer could average normal to below normal in the east. He tweeted today that June will average normal to below in the Great lakes region. It will be interesting to see how that turns out. It's interesting how cool summers seem t oshow their face in June. Take 1816 and 1992 for example. I well remember the cold front of May 24-25, 1992 as I had received a new baseball glove for my birthday and found it difficult to break into given the weather was abnormally cold the last week of May that year. Also, New England saw snow the first week of June 1816. Now, I'm not saying we're going to get anything like that - there's been no massive tropical volcanic eruption for one thing!

Ottawa Blizzard,

I suspect that the first half of the month might well see cooler readings outduel warmer ones in at least parts of the Great Lakes region. My worry is that some of the analogs showing up, especially if the transition to El Niño is rather slow, could lead to a very warm closing 7-10 days of the month. Given some of the numbers from those years, the potential would exist for that warmth to wipe out the cool anomalies that might have accumulated during the first half of the month (eastern Great Lakes area including the Toronto Metro Area probably have a better chance of being cool than the western Great Lakes region). Recent runs of the CFSv2 hint at such an outcome, as well.

In the end, it will be interesting to see how things work out. I, for one, hope that no matter what the June or summer outcome, winter 2012-13 will be a vast improvement (colder, snowier) than the past one (especially for areas where cold winters are much more important for the economy).

[donsutherland1]

I agree Don about the first half of June. I'm a little concerned or coastal areas of New England as onshore flow could much things up..especially next week. My guess BOS throws up - departures during this time. That's a good -NAO block right now.

I share your concern about the persistence of the onshore flow, as well. Right now, the idea of a period of much above normal readings toward the end of the month is still so far off that it is more speculation than anything. It will be interesting to see how the pattern evolves over the next few weeks. Recent runs of the CFSv2 keep New England and areas along the coast farther south on the cool side of normal for the month as a whole. Given that the model is in a timeframe where it has shown skill, a cooler outcome than what I expect is a plausible scenario.

[donsutherland1]

All it takes is a parade of these cut off systems like the one later this week to do the deed and thus send temps into the -negative side regardless of how much above normal temps are across the Arctic. Was either 2008 or 2009 that had that sort of thing?

But yeah i strongly believe June will end up on the -negative side in this region and NE.

I don't disagree with you about the risk you describe. For me, the forecast for the Great Lakes and New England was a very close call, especially for the June-August period as a whole.

[Isotherm]

Ensembles indicate a rapid relaxation of the NAO block by days 7-10, at which time the strong upper ridge centered in the Plains will begin to propagate eastward in pulses. Flow will probably go more zonal by June 10th-15th with plenty of warmth and humidity in the Northeast. I agree that June 1-7 looks quite cool, especially for the coastal Northeast, but I'd personally be shocked if June finished below normal temp wise for the majority of the East. I could see an area of slightly below normal across the northern Great Lakes, but the warmth has been very persistent lately.

Canada continues to run above normal for the most part, and once this strong -NAO block weakens, there's really nothing preventing above normal temps in the East. Additionally, the transition to Nino is occurring slowly, more slowly than many cool summer analogs. Right now we're near 0 in region 3.4. 2009 was already around +0.5c by this point in time. I agree with Don that the warmth should outduel the cool for most of the US for both June and this summer.

[PottercountyWXobserver]

Put me into the camp of above average temps to close out the month of June. As soon as this -NAO block weakens, I can see the midwest ridge expand into the east in pulses as isotherm eluded to. With the very slow progression of the El Nino compared to most analogs, I'm thinking the persistant cool weather doesn't dominate until the middle of July. Infact I could see a very warm period from the last week of June to the first week of July as being well above average then the pattern switches in the middle to the end of July. I expect August to come in very cool, maybe -2 or -3 departures for the month in the Great Lakes and parts of the East Coast.

[easternsnowman]

Put me into the camp of above average temps to close out the month of June. As soon as this -NAO block weakens, I can see the midwest ridge expand into the east in pulses as isotherm eluded to. With the very slow progression of the El Nino compared to most analogs, I'm thinking the persistant cool weather doesn't dominate until the middle of July. Infact I could see a very warm period from the last week of June to the first week of July as being well above average then the pattern switches in the middle to the end of July. I expect August to come in very cool, maybe -2 or -3 departures for the month in the Great Lakes and parts of the East Coast.

I agree

[Srain]

A very different pattern is shaping up this week compared to last year for the Southern Plains (Texas/Oklahoma/Louisiana) . A robust 5H low traversing NE out of NE Mexico merging with a warm core 5H dropping S along a stalling frontal boundary with a surge of deep tropical moisture with near 2.0 pw's flowing NW from the W Caribbean and Gulf will bring heavy rainfall chances with some flooding potential as the Omega block over the Ohio Valley remains entrenched and a trough to the W deepens increasing wildfires across Arizona and New Mexico.

[Srain]

^

HPC is suggesting a transition to a warm core low is possible...

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

553 AM EDT TUE JUN 05 2012

FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION

VALID JUN 05/1200 UTC THRU JUN 08/1200 UTC

REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1...

06Z UPDATE... NO SIGNIFICANT CHANGES FROM PREVIOUS ISSUANCE BASED

ON THE 00Z EC... 03Z SREF MEAN AND 06Z NAM.

...SOUTHEAST/GULF COAST STATES...

THE COMBINATION OF A WELL DEFINED MID-LEVEL VORT NEAR CENTRAL MS

EARLY THIS MORNING AND A FRONTAL BOUNDARY NEAR THE TN VLY INTO THE

SRN APPALACHIANS SHOULD IGNITE ANOTHER ROUND OF POSSIBLE ORGANIZED

HEAVY RAINFALL FROM THE SOUTHEAST COAST WESTWARD TO THE

ERN/CENTRAL GULF COAST. THE VORT MAX SHOULD SLIDE DOWNSTREAM TODAY

FROM CENTRAL MS TO THE PANHANDLE OF FL OR NRN FL... WHILE THE

AMPLIFIED UPPER TROUGH OVER THE NERN QUAD OF THE COUNTRY HELPS

LOWER HEIGHTS AND STEER THE COLD FRONT SOUTH AND EAST INTO THE

SOUTHEAST/SOUTH. THE MODEL GUIDANCE APPEARS TO HAVE A DECENT

HANDLING OF THE SURFACE BOUNDARY PROGRESSION BUT IS NOT HANDLING

THE SMALL SCALE MCS VERY WELL THIS MORNING. NEEDLESS TO SAY...

ENOUGH LIFT AND INSTABILITY AHEAD OF BOTH FEATURES WITH AOA 1.75

INCH PWS SHOULD BE SUFFICIENT FOR POSSIBLE HEAVY RAINFALL FROM

SERN LA TO COASTAL GA/SC. HPC GENERALLY FOLLOWED A BLEND OF THE

OPERATIONAL ECMWF WITH THE SREF MEAN AND INTERNAL PSEUDO BIAS

CORRECTED GUIDANCE FOR POSSIBLE 1 TO 3 INCH AMOUNTS.

...TX...

A SHEAR AXIS PRESENT ACROSS THE TX PANHANDLE/WEST TX WITH AOA 1.5

INCH PWS IS FUELING ORGANIZED CONVECTIVE HEAVY RAINFALL AND THIS

MID-LEVEL FEATURE APPEARS TO EITHER BECOMING BETTER ORGANIZED OVER

THE NEXT 24 HRS OR THE MODEL GUIDANCE IS SLOW IN CAPTURING THE

FEATURE BASICALLY TRAPPED UNDER THE PLAINS RIDGE. THUS THE

MID-LEVEL VORT/LOW SHOULD NOT MOVE MUCH OVER THE NEXT 24 HRS... AS

850MB WINDS ARE GENERALLY 5-10 KTS OR LESS. HPC GENERALLY FOLLOWED

A COMBO OF THE ECMWF AND GFS WITH THIS SMALL SCALE FEATURE AND

TRENDED MORE CLOSELY TOWARD THE GFS ON HEAVIER QPF AMOUNTS...

DESPITE THE GFS DEPICTING POSSIBLE CONVECTIVE FEEDBACK BULLS-EYE.

HPC GENERALLY WENT WITH A SIMILAR AXIS FROM SERN CO/TX PANHANDLE

SEWRD INTO CENTRAL TX FOR ANOTHER DIURNAL SURGE OF INSTABILITY

WITH THE DEEPER MOISTURE FOR HEAVY RAINFALL THIS AFTN PERSISTING

INTO THE OVERNIGHT HRS... WITH 1 TO 3 INCH AMOUNTS.

...NW/NRN ROCKIES...

A DEEP AND ANOMALOUS UPR TROUGH WILL SWEEP UP THROUGH THE NWRN

QUAD OF THE COUNTRY ON TUES... WHILE GOING NEG TILT. A SHORT WAVE

IMPULSE IS ALREADY LIFTING THROUGH THE INTERIOR NW EARLY THIS

MORNING... WITH ANOTHER POTENT JET STREAK ROUNDING THE BASE OF THE

UPPER TROUGH LIFTING FROM NRN CA TO WRN MT. THIS SHOULD EXIT THE

INITIAL HEAVY RAIN/PRECIP SHIELD OUT OF THE INTERIOR NW/NRN

ROCKIES INTO WRN CANADA BEFORE ANOTHER PRECIP MAX TAKES FORM ON

THE BACKSIDE OF A PROGGED SURFACE LOW AND NEAR AN INVERTED SURFACE

TROUGH OVER NWRN MT. THE RESULTANT SHOULD BE ORGANIZED MDT TO HVY

RAINFALL FROM CENTRAL ID/WRN MT NORTH INTO CANADA... AS MOIST

SERLY FLOW CONTINUES. HPC GENERALLY FOLLOWED A BLEND OF THE

OPERATIONAL GFS AND ECMWF FOR QPF AMOUNTS.

DAYS 2 AND 3...

...SOUTHEAST U.S./FLORIDA...

ONE AREA TO WATCH FOR POTENTIALLY HEAVY RAIN IN THE DY2-3

PERIOD...IS NORTHERN FLORIDA AND PERHAPS FAR SOUTHERN GEORGIA. A

PLUME OF HIGH-PW AIR WILL WORK ITS WAY UP FROM THE CENTRAL

GULF...AND BECOME CAUGHT IN THE WESTERLIES. THIS AIR MASS SHOULD

PROMOTE ISOLATED TO SCATTERED VERY HEAVY DOWNPOURS. BROAD SCALE

ORGANIZATION...HOWEVER...IS MORE QUESTIONABLE. THOUGH THERE WILL

BE BROAD LOW LEVEL CONVERGENCE...THE BULK OF THE MID AND UPPER

LEVEL FORCING - ASSOCIATED WITH A RESIDENT LONGWAVE TROUGH AND

ENTRANCE REGION OF AN ASSOCIATED JET STREAK - WILL REMAIN NEAR AND

JUST EAST OF THE COASTLINE. MEANWHILE...DEEP CONVECTION WITHIN THE

HIGH-PW PLUME OVER THE GULF...MAY TEND TO PROPAGATE SOUTH AND

WESTWARD INTO THE MOISTURE AXIS...PLACING A SECOND PRECIP MAXIMUM

OFF THE WEST COAST OF FLORIDA. ACTIVITY OVER

LAND...THEREFORE...MAY BE LARGELY DRIVEN BY DIURNAL EFFECTS.

THUS...WHILE THERE WILL BE POTENTIAL FOR VERY HEAVY LOCAL

DOWNPOURS...THERE IS NOT YET ENOUGH OF A LARGE SCALE SIGNAL TO

DRAW AN EXCESSIVE RAIN THREAT.

...TEXAS...

TEXAS WILL BE A SECOND AREA OF STRONG INTEREST. HERE A MID LEVEL

TROUGH WAS PINCHING OFF FROM THE FLOW...AND BECOMING TRAPPED

BENEATH A SHORTWAVE RIDGE DEVELOPING IN THE CENTRAL PLAINS STATES.

DIURNAL BUILD UP AND RELEASE OF INSTABILITY/LATENT HEATING...SUCH

AS WAS TAKING PLACE THIS MORNING IN WEST TEXAS...WILL SUSTAIN THE

MID LEVEL LOW THROUGH DAY 3. FLORIDA STATE PHASE SPACE PLOTS SHOW

SOME TENDENCY FOR THIS SYSTEM TO DEVELOP A WARM CORE WITH

TIME...WHICH AT A QUICK GLANCE...DOES SHOW UP IN THE GFS...WITH

WARMING AT 700-500 MB. THE 00Z ECMWF IS GOOD ON THE LARGE

SCALE...BUT IS PERHAPS OVER-FORECASTING THE WARM CORE CHARACTER OF

THIS SYSTEM...AS THAT MODEL KEEPS A CONCENTRATED AREA OF HEAVY

RAIN TIED DIRECTLY TO THE MID LEVEL LOW THROUGH THE FULL 24 HOURS

OF THE DAY 3 PERIOD. THIS RESULTS IN WHAT IS PROBABLY AN

UNREALISTIC 9-INCH PLUS QPF TOTAL OVER NORTH TEXAS. SINCE THE

LOCATION AND ORIGIN OF THIS FEATURE FAVORS AT LEAST MODEST COLD

POOL GENERATION...WE PREFERRED SOLUTIONS SUCH AS THE NAM AND 00Z

GFS...WHICH PROGRESS THEIR QPF SIGNAL SLOWLY SOUTH AND EAST WITH

TIME.

[donsutherland1]

Some morning thoughts:

1. I was a little slow with the timing for the recent cool weather in June (favoring the June 8-15 period for cool anomalies vs. the June 1-7 timeframe) in Messages #1 and #9.

2. In Mesage #9, I also noted that among the analogs showing up for the second week of June are 1953, 1966, 1969, and 1977. All four of those years witnessed excessive heat in the closing 7-10 days of June. Moreover, 1969 was the leading June analog.

3. All four of those years also witnessed warmer than normal July readings in the CONUS. With the exception of New England, the eastern two-thirds of the U.S., along with southern Ontario (including the greater Toronto area) saw warmer than normal readings.

4. The latest run of the CFSv2 shows a lot of warmth in the June 20-26 timeframe. For July, the CFSv2 is a sea of warmth across most of North America with scorching heat covering much of the eastern U.S. and warm anomalies throughout eastern Canada.

5. These latest developments increase my confidence in my summer idea that near normal temperatures with some scattered cool anomalies could be present in the Great Lakes and New England areas, but much of the U.S. and Canada will likely have warm anomalies. Overall, summer 2012 does appears to be on a course to see warm anomalies outduel cool ones for the CONUS and North American continent as a whole, even as the recent unseasonable chill might lead one to believe a summer with widespread cool anomalies lies ahead.

6. The late July and August timeframe continues to have the greatest uncertainty. There is the potential that some parts of North America could witness a flip to cool anomalies.

[DaculaWeather]

So far here in Atlanta we've been below normal for June.

Last year I averaged 81.2º for the first 5 days of the month, so far this year I've averaged 68.1º. The normal average is 71.5º for the first 5 days.

[uncle W]

Some morning thoughts:

1. I was a little slow with the timing for the recent cool weather in June (favoring the June 8-15 period for cool anomalies vs. the June 1-7 timeframe) in Messages #1 and #9.

2. In Mesage #9, I also noted that among the analogs showing up for the second week of June are 1953, 1966, 1969, and 1977. All four of those years witnessed excessive heat in the closing 7-10 days of June. Moreover, 1969 was the leading June analog.

3. All four of those years also witnessed warmer than normal July readings in the CONUS. With the exception of New England, the eastern two-thirds of the U.S., along with southern Ontario (including the greater Toronto area) saw warmer than normal readings.

4. The latest run of the CFSv2 shows a lot of warmth in the June 20-26 timeframe. For July, the CFSv2 is a sea of warmth across most of North America with scorching heat covering much of the eastern U.S. and warm anomalies throughout eastern Canada.

5. These latest developments increase my confidence in my summer idea that near normal temperatures with some scattered cool anomalies could be present in the Great Lakes and New England areas, but much of the U.S. and Canada will likely have warm anomalies. Overall, summer 2012 does appears to be on a course to see warm anomalies outduel cool ones for the CONUS and North American continent as a whole, even as the recent unseasonable chill might lead one to believe a summer with widespread cool anomalies lies ahead.

6. The late July and August timeframe continues to have the greatest uncertainty. There is the potential that some parts of North America could witness a flip to cool anomalies.

1969 was the coolest of the bunch but was still above average for the Summer and thru September...1953 had NYC's longest heat wave late August into early September...1966 was hot and dry throughout...1977 was hot also...1969 was the only year without a 100 degree temperature...

[SACRUS]

1969 was the coolest of the bunch but was still above average for the Summer and thru September...1953 had NYC's longest heat wave late August into early September...1966 was hot and dry throughout...1977 was hot also...1969 was the only year without a 100 degree temperature...

MEI value for Apr/May is in. Same as 1969

MEI Value Apr/May: .706

closest actuals

1969: .706

1991: .719

1958: .743

2005: .758

1990: .595

1953: .840

[uncle W]

MEI value for Apr/May is in. Same as 1969

MEI Value Apr/May: .706

closest actuals

1969: .706

1991: .719

1958: .743

2005: .758

1990: .595

1953: .840

interesting stat...It's in El Nino territory...

[SACRUS]

interesting stat...It's in El Nino territory...

I was surprised by the high value as well, we'll see how we track next month perhaps hovering close to around the same value.

[donsutherland1]

June 16-22, 2012 Thoughts:

The June 16-22 period is likely to feature widespread warmth. At the same time, there is a growing possibility that an unseasonably hot air mass could be heading eastward toward the end of the period, setting the stage for a hot final week of the month in the Ohio Valley, Mid-Atlantic, and Northeast regions.

The chart below is as follows:

The composite temperature anomalies for ENSO Region 3.4 anomalies of -0.2°C to +0.5°C, a PNA of -1.25 to -0.25, and an AO of -0.50 to +0.50 for North America.

Taking into consideration the ensemble guidance, NAEFS, and CFSv2, I suspect that there will be more warmth than what the teleconnection analogs suggest.

My thoughts are as follows:

- Cool along the West Coast of the U.S.

- Generally warmer than normal across Canada and Alaska

- Warmer than normal across the remainder of the U.S. with the warmest anomalies in the Plains States.

[JamieOber]

Don, been fairly wet in the East recently - do you expect that trend to continue? Also, will it have any effect on temps?

[donsutherland1]

Don, been fairly wet in the East recently - do you expect that trend to continue? Also, will it have any effect on temps?

Apologies for the delayed reply. Right now, I don't see any big changes in the pattern. Hence, I suspect that the next 30-45 days and perhaps longer could see above normal precipitation.

[donsutherland1]

June 23-30, 2012 Thoughts:

The final week of June appears likely to witness the warmest readings relative to normal in parts of the East. In fact, compensating for the shorter wavelengths, much of North America looks to be warmer than normal. Moreover, with some hot analogs showing up, it appears increasingly likely that the first week of July could experience warmer than normal temperatures, too. Among the hot analogs appearing are 1966, 1969, 1977, and 1980. In fact, the latest run of the CFSv2 has much of North America and Eurasia warmer to much warmer than normal for July. Right now, it's too soon to make a definitive call for July, but some hot analogs have persistently been in the mix.

The charts below are as follows:

Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of -0.2°C to +0.6°C, a PNA of -1.00 to 0.00, and an AO of 0.00 to +1.00 for North America.

Right: NAEFS (June 21-27, 2012 forecast)

All said, my thoughts are as follows:

- West Coast of the U.S. into British Columbia eastward into Alberta: cooler than normal.

- Southwestern U.S. much warmer than normal

- Remainder of North America warmer than normal with perhaps the Southeast being close to normal due to wetness and an area running from the Great Lakes to the Northeastern U.S. and across Quebec and portions of Atlantic Canada having the potential to be much warmer than normal.