Site log - Melbourne (Mar 1998) Flags: 1-Satellite coincidence data 2-Scan in TSDIS data 3-Scan not in TSDIS data A-Major problem (moderate to strong AP &/or widespread coverage) B-Minor problem (weak AP &/or very litte coverage) ******************************************************************************************************* 01 Mar 98: Convection from previous days system continues to move out of range to the east, early on. Another strong convective system begins moving in from the west around 02Z while more cells in between the systems begin firing. Line of strong storms and stratiform rain continues to track across scope through 08Z while at the same time a very lage isolated cell moves northward, ahead of the line. By 0830Z, the northern part of the line races ahead and bows out while the southern part of line breaks apart, leaving very strong isolated convective cells in its wake. Small, V-notch supercell with mesocyclone present from 0817-0832Z. Line with trailing isloated cells continues off to the east and out of range but more strong convection moves in from the south (09Z) while another cluster moves in from the west around the same time. Larger, more coherent region of strong convection and heavy stratiform rain moves in from the SW around 11Z. After data gap, all convection is gone but significant area of light stratiform rain persists until that to is eventually out of range. Data processed: 0004-1337 Z 1716-2354 Z Satellite coincidence: 0651Z(159 km), 0827Z(582 km), 1141Z(366 km), 1317Z(548 km) QC notes: 0029-0039Z: moderate-to-intense AP splotch remaining SE of radar -----> corrected. Raising Z3 to 6.0 km worked like a charm in that it removed the intense specks but did not touch the precip in either the base scan or the next tilt up. When manipulating Z3, it is always important to be wary of removal of precip from higher level scans. 0049-0244Z: scattered weak-to-moderate-to-intense AP splotches 3B !!FLAG!! -----> Almost completely corrected except for two VOS's (0234 and 0239Z). I felt bad flagging this time period because the new parameters did such a good job but it can't be avoided. The two VOS's in question still contain some weak AP splotches NW of the radar which could not be removed without removing light precip. VOS 0234Z was moved to the bad_files_not_in_1C.hdf directory...hence the 3B flag. 0309-0324Z: moderate-to-intense-to-weak AP specks W of radar -----> corrected 0612-0847Z: shaving away of precip on backside of line and backside of large cells SE of line -----> corrected 0612-0724Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 0732-0747Z: intense AP splotch remaining N of radar 2A !!FLAG!! -----> could not remove intense AP without compromising light (and even moderate) precip in the field. Hurts to leave it in but precip is always the number one priority. ******************************************************************************************************** 02 Mar 98: Thin line of weak convection out over the ocean early on quickly moves out of range. More serious looking convective cells fire up south of the radar, near 150 km cutoff, around 05Z. THis line of strong, isloted cells is out of range by 10 Z. No more precipitation occurs for the rest of the day. Data processed: 0000-2355 Z Satellite coincidence: 0538Z, 0715Z, 1028Z, 1205Z QC notes: 0040-0225Z: removal of light precipitation -----> corrected 0544-0722Z: removal of light precipitation -----> corrected 0741-0851Z: weak-to-moderate-to-intense AP remaining SW to S of radar 2A !!FLAG!! -----> slightly improved with new parameters but the best thing going for us is that most of the AP is beyond 150 km. Using a convective/ stratiform 2A-54 product image which extends to only 150 km, it is confirmed that VOS's 0801-0831Z are the only ones with AP extending inside the 150 km range ring. The major flag is for these VOS's. 0911-0931Z: moderate AP remaining S of radar -----> corrected. Reduced AP so that any remaining false echo is beyond 150 km and therefore, not a worry. Confirmed the 150 km range by creating 2A-54 image to determine if any AP made it in....it did not. 0951-0956Z: moderate-to-intense AP remaining S of radar -----> corrected. Reduced AP so that any remaining false echo is beyond 150 km and not a concern (confirmed with 2A-54 c/s image) 1535-1732Z: chaff echo remaining -----> corrected. Echo confirmed as chaff by satisfying 4 criteria and promptly removed. 2108-2355Z: chaff echo remaining -----> corrected ******************************************************************************************************* 03 Mar 98: No precipitation on this day. Data processed: 0005-2358 Z Satellite coincidence: 0602Z, 0739Z, 1052Z, 1229Z QC notes: 0005-0756Z: chaff echo remaining -----> corrected. Confirmed as chaff and removed. 0934-1231Z: chaff echo plus weak AP remaining -----> corrected. 2150-2358Z: chaff echo remaining -----> corrected. Confirmed as chaff and corrected. ******************************************************************************************************* 04 Mar 98: No precipitation on this day. Data processed: 0008-2355 Z Satellite coincidence: 0450Z, 0626Z, 0940Z, 1116Z QC notes: 0008-0759Z: chaff echo remaining -----> corrected. Confirmed as chaff and removed. 1544-2059Z: chaff echo remaining -----> corrected. Confirmed as chaff and removed. 2157-2355Z: chaff echo remaining -----> corrected. Confirmed as chaff and removed. ******************************************************************************************************* 05 Mar 98: Only precipitation on this day in the form of one or two very weak showers after 14Z and then some more moderate showers skirting the northern edge of the scope after 23Z. Data processed: 0005-2358 Z Satellite coincidence: 0513Z, 0650Z, 0827Z, 1004Z QC notes: 0005-0954Z: chaff echo remaining -----> corrected 1330-1340Z: weak AP remaining (no precip present) -----> corrected ******************************************************************************************************* 06 Mar 98: Weak precipitation shield hangs out at the NW radar fringe early on. A glimpse at only two VOS's available later in the day show only some weak cells off to the northeast and at considerable range from the radar. Data processed: 0008-0344 Z 1327-1332 Z Satellite coincidence: 0401Z, 0537Z, 0851Z, 1027Z QC notes: no problems for the limited data we have on this day ******************************************************************************************************* 07 Mar 98: Only one VOS on this day (2116Z), so basically treated like an entire day of missing data. ******************************************************************************************************* 08 Mar 98: Only precip during the period for which we have data on this day is in the form of small, extremely weak showers off the coast. Data processed: 1719-2351 Z Satellite coincidence: 0312Z, 0449Z, 0803Z, 0939Z QC notes: 2223-2351Z: removal of light precipitation -----> corrected ******************************************************************************************************* 09 Mar 98: Very intense squall line moves across the scope from west to east, bringing heavy rain and strong convection. The data gap at the end of the day does is not a problem since all precip is out of range by the beginning of the gap. Data processed: 0001-1405 Z Satellite coincidence: 0200Z(680 km), 0337Z(284 km), 0650Z(634 km), 0827Z(49 km!!) QC notes: 0001-0140Z: removal of light precipitation -----> corrected 0602-0907Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 0736-0808Z: weak-to-moderate-to-intense AP splotches remaining behind the line 3A !!FLAG!! -----> could not removed intense AP splotches from VOS's, 0741-0746Z. Luckily, the VOS's near 08Z which will be included into that great satellite coincidence granule were successfully corrected. 0746Z: precip-eating mode + moderate-to-intense AP splotches remaining 3A !!FLAG!! -----> unexpected removal of precip within a 50km radius of the radar, dubbed preci-eating mode, was corrected by turning off Z0. Removed one of two intense AP splotches by bumping up dBZ noise but could not remove the other one without affecting the precip present...hence the flag. 0823-0903Z: shaving away of precip on the backside of the squall line -----> corrected 1321Z: moderate-to-intense AP remaining SW of radar -----> confirmed by creating convective/stratiform 2A-54 map that AP is beyond 150 km and is therefore not a concern. Logic is that the c/s map only extends to 150 km so if AP is not present on this map, it can be neglected....it serves as a 150 km range ring. 1340-1400Z: moderate-to-intense AP remaining SW of radar -----> c/s maps were made for all VOS's in this time period which showed that the AP did not surface in these images, meaning it was beyond 150 km, and therefore not a concern for us. ******************************************************************************************************** 10 Mar 98: No precipitation on this day. Data processed: 1324-2352 Z Satellite coincidence: 0224Z, 0401Z, 0715Z, 0851Z QC notes: 1650-2352Z: chaff echo remaining -----> corrected. Verified as chaff (on satellite and radar/gauge images) and removed. ******************************************************************************************************** 11 Mar 98: No precipitation on this day. Data processed: 0002-2354 Z Satellite coincidence: 0112Z, 0248Z, 0602Z, 0739Z QC notes: 0002-0951Z: chaff echo remaining -----> corrected. Verified as chaff and removed. 1455-1534Z: chaff echo remaining -----> corrected. Verified as chaff and removed. 1633-2354Z: chaff echo remaining -----> corrected. Verified as chaff and removed. ******************************************************************************************************** 12 Mar 98: No precipitation on this day. Data processed: 0005-2357 Z Satellite coincidence: 0136Z(37 km), 0313Z, 0449Z, 0626Z QC notes: 0005-0459Z: chaff echo remaining -----> corrected. Verified as chaff and removed. 1546-2357Z: chaff echo remaining -----> corrected. Verified as chaff and removed. ******************************************************************************************************** 13 Mar 98: Stationary North-South line of showers and convective cells off the coast from ~08Z through the end of the day. The incredible lack of movement of this line, given the definite eastward track of chaff also present on this day, plus the fact that the radar is in clear-air mode made me ponder the validity of these "cells" but they are confirmed by satellite imagery so they will be treated as real echoes (they look real, they just don't act real). I would love to see this line in some mesonet data in order to look for some areas of convergence....but now I am qc'ing in fantasyland. :) Data processed: 0008-2350 Z Satellite coincidence: 0023Z, 0200Z, 0514Z, 0650Z QC notes: 0008-0610Z: chaff echo remaining -----> corrected 0828-1708Z: removal of light precipitation -----> corrected 1718-2350Z: removal of light precipitation + chaff echo present (this is a first the combination and may be unfixable) 2A! !!FLAG!! -----> good news and really bad news....the good news is that all precip which was removed during first-pass processing was successfully returned to the field. The really bad news is that the significant chaff echoes which are present at the same time could not be removed. The QC algorithm treats chaff like precip which means any parameter settings I use to remove the chaff will also remove the precip present at the same time. Since precip is the number one priority, all chaff is left in (except a small bit very close to the radar which is removed). There also seems to be some interaction between the cells to the NE and chaff, after 23Z. Anyways, the chaff is the reason for the major flag. ********************************************************************************************************* 14 Mar 98: Stationary N-S line of showers remains off the coast, in roughly the same location for the entire day (very peculiar). THis line is the only form of precip on this day. Data processed: 0000-2353 Z Satellite coincidence: 0245Z, 0422Z, 0559Z, 0735Z, 0912Z, 2355Z QC notes: 0000-0613Z: removal of light precipitation (be wary of weak chaff which is present until 0158Z) 2A-,2B !!FLAG!! -----> the light precip problem was corrected. Flag is for some chaff present early on which could not be completely removed. The flag goes from A- to B as the coverage of chaff shrinks with time. The coverage is never as large as the previous day and the reflectivity of the chaff is very weak at all times. 0623-1305Z: removal of light precipitation + scattered weak-to-moderate AP remaining 1B,1A,2A !!FLAG!! -----> for Melb, the worst QC combination is trying to fix precip removed by the default parameters while also trying to remove AP at the same time. THe first involves lightening up on the parameters while the latter is usually accomplished by increasing the parameters. Obviously, the two are like oil and water and that is the case here. It was almost impossible to remove any AP while trying to re-introduce light precip simultaneously. Since precip always take precedence, all light precip was re-introduced but much AP is also present. I am embarrassed to pass some of these VOS's along but I have tried everything to remove the AP and not touch the light precip and this is the "best" result....hence the major flags. (luckily the overpasses in this time period are not close) 1315-2353Z: removal of light precipitation 2B-,1A- !!FLAG!! -----> all precip removal problems were corrected but some weak AP was re-introduced at times. THe B- flag is for the isolated and scarce weak AP specks which show up in a few VOS's early in this time period. Obviously from the flag prioritization, these specks are considered very minor. After 23Z, the weak AP gets more coverage and some emabedded moderate AP splotches can be found. Could not remove this AP without affecting the line of light showers off the coast. Originally had this latter flag as a B+, but re-considering the coverage of the AP by day's end led me to upgrade the flag to A-. ********************************************************************************************************* 15 Mar 98: Only precip on this day is the line of showers which continue to persist off the Florida coast until roughly 19Z, when they finally dissipate (after almost 3 days). Data processed: 0003-2357 Z Satellite Coincidence: 0111Z, 0425Z, 0601Z, 2358Z QC notes: 0003-0300Z: removal of light precipitation 1B,2A-,3A,3B !!FLAG!! -----> most of light showers which were originally removed were re-introduced to the field. Unfortunately, turning down the prarameters to allow for this re-introduction also brought back scattered specks and splotches of AP. The severity of the flag is determined by the intensity of the reflectivity present at any given time. VOS's 0033Z, 0201Z, 0230Z, and 0300Z were moved to bad_files_not_in_1C.hdf directory. All in all, not a fun time period to perform quality control. 0310-0428Z: weak AP N of radar is NOT a concern since it is beyond 150 km. (confirmed with 2A-54 convective/stratiform image) 0438-0458Z: moderate AP specks remaining -----> corrected. Some very light showers were eliminated in the process but felt the trade-off was worthwhile and in our favor. Also, some very small, weak AP specks remain within 150 km but they are considered negligible and thus no flag. 0517-0734Z: removal of light precipitation (be wary of AP also present and can easily be brought back when bring params down for the light precip) 1B, 2B !!FLAG!! -----> light precip problem corrected. Some weak AP brought back in along with 2-3 small but intense specks of AP but the good news is that probably 95% of this false echo is beyond 150 km and therefore of no concern to us. The intense specks are all beyond 150 km....hence no major flags. The minor flags are for the 5% of weak AP which is within 150 km. 0744-0804Z: weak/moderate AP remaining SE of radar + removal of light precip 3A !!FLAG!! -----> light precip removal problem corrected. But, nothing could be done about the AP which remained. Any aggressive attempt to remove the false echo resulted in the removal of moderate of precip as well. VOS 0804Z was moved to bad_files_not_in_1C.hdf directory. 0814-0913Z: removal of light precipitation 3A- !!FLAG!! -----> all precip removal was corrected. The A- flag is for one VOS, 0824Z, which contains an intense AP splotch just within 150 km which could not be removed without compromising the precipitation. If it weren't for this one VOS, this time period would now be problem-free. 1051-1249Z: widespread weak/moderate AP remaining 2A !!FLAG!! -----> improved but splotches of moderate AP remain. Could not remove this AP without significantly affecting precip present. All of the weak AP remaining along the outer scope is beyond 150 km and not a concern. Some light precip was also removed in the process of reducing the AP but not a concern since any significant removal was of true echo beyond 150 km. 1308-1849Z: removal of light precipitation 2B, 2A !!FLAG!! -----> precip removal problem corrected....but it brought some AP back with it. The minor flag is for VOS's 1308-1354Z where some very weak AP splotches remain (hardly a concern). The major flag is for VOS's 1549-1659Z where a persistent speck of moderate AP remains near the radar. Neither of these false echo problems could be rectified without compromising the light precip present so they allowed to persist and have been flagged accordingly. 2244-2357Z: horrifically intense AP remaining (no precip present) -----> corrected *********************************************************************************************************** 16 Mar 98: No precipitation on this day. Data processed: 0001-2356 Z Satellite Coincidence: 0135Z, 0312Z, 0449Z, 2246Z QC notes: 0001-0122Z: horrifically intense AP remaining (no precip present) -----> corrected 0132-1357Z: scattered weak/moderate AP remaining (no precip present) -----> corrected 1734-2356Z: chaff echo remaining (no precip present) -----> corrected. Verified as chaff (by satellite and radar mosaic composites) and removed. *********************************************************************************************************** 17 Mar 98: Scattered showers and small convective cells over the Atlantic for most of the day. Data processed: 0006-2356 Z Satellite Coincidence: 0135Z, 0312Z, 0513Z, 2134Z, 2310Z QC notes: 0006-0807Z: chaff echo remaining (no precip present) -----> corrected. Confirmed as chaff and removed. 0817-1104Z: removal of light precipitation (be wary of AP present) 2B !!FLAG!! -----> precip removal problem corrected. But, could not completely remove very weak chaff echo which remains south of the radar. Some very weak splotches of this false echo remains because no parameter setting scenario would allow me to remove the chaff without removing the very sensitive, light precipitation....hence the minor flag. 1222-2252Z: removal of light precipitation (be wary of AP present) -----> corrected *********************************************************************************************************** 18 Mar 98: Early on, showers and convective cells stream NW from the ocean to over mainland Florida in two distinct bands. This convection dies down a bit by 06Z but activity still present all scattered cells and showers continue to fire. Some stronger convective cells present NE of the radar by 13Z. By 18Z, showers begin to quickly materialize over Florida and intensify into strong convective cores. By 22Z, a large convective cluster is present just east of the radar while another moves in from the NW...both with significant rainfall. Data processed: 0003-2358 Z Sateliite Coincidence: 0224Z(600 km), 0400Z(124 km), 2158Z( 10 km!), 2334Z(652 km) QC notes: 0003-1813Z: removal of light precipitation -----> corrected 1628-1743Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 1823-2058Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 2153-2258Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected *********************************************************************************************************** 19 Mar 98: At start of day, convection begins as intense isolated convective cells east of the radar which put down an appreciable amount of stratiform precipitation as old cells dissipate new cells continue to form. At the same time, a strong mesoscale convective system begins to enter the western edge of the scope and is moving east very quickly. Meanwhile, some of the cells east of the radar have become supercellular, having distinct mesocyclones. A meso is evident in the most intense cell from 0038-0058Z. After this cell entrains the weaker cells south of it, it is once again isolated, with nothing stealing its inflow and it really begins to intensify. A long-lived mesocyclone and numerous hook echoes are evident with this supercell from 0448-0903. The meso signature (in VR images) from 0618-0723Z is one of the strongest and most prominent I have ever seen. As this cell continues to grind over the Atlantic, the strong squall line continues to track eastward across Florida and eventually overtakes the isolated cells out ahead of it. A very strong bow echo is evident south of the radar from 0813-11Z. The squall line exits the scope to the east leaving stratiform rain in its wake. However, shortly after the squall's departure, more convective cells begin to fire north and west of the radar. By 20Z, a second intense MCS enters the scope from the west, and strong convection with significant stratiform rain ensues right through the end of the day. Data processed: 0003-2242 Z Satellite Coincidence: 0111Z(746 km), 0248Z(253 km), 0424Z(730 km), 2045Z(446 km), 2221Z(427 km) QC notes: 0303-0418Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 0528-1348Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 1128-1428Z: moderate/horrifically intense AP remaining N to NW of radar 2A+, 2A !!FLAG!! -----> believe it or not, some improvement was made. Most, if not all, of the moderate Ap specks and splotches N of the radar were removed. But the more serious problem of intense AP NW of the radar remains. Both embedded and non-embedded, very intense AP remains and could not be removed without significantly compromising the precipitation present. In all, a horrible time period and am thankful that no overpass occurs during these 3 hours. 1438-1443Z: moderate radial spike remnants remaining N of radar -----> corrected 1503Z: intense radial spike remnants remaining N of radar 3A !!FLAG!! -----> could not remove splotch without significantly compromising precip present in the field. Moved VOS to bad_files_no_in_1C.hdf directory...hence the 3A flag. 1626-2242Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 1715Z: precip-eating mode (~50km ring of missing precip surrounding radar) -----> corrected 1833Z: precip-eating mode -----> corrected 2242Z: precip-eating mode -----> corrected ************************************************************************************************************ 20 Mar 98: Widespread, intense convection and copious rainfall for the limited amount of data we have on this day. Data processed: 2213-2358 Z Satellite Coincidence: 0135Z(536 km), 0312Z(250 km), 2109Z(101 km), 2245Z(696 km) QC notes: 2213Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected 2258-2328Z: 10 km ring of missing precip surrounding radar (Z2 too high) -----> corrected ************************************************************************************************************ 21 Mar 98: Strong convection remains off the coast very early on but is beyond 150 km from the radar by 0130Z. No precipitation within this range over the remainder of the day. Data processed: 0003-2356 Z Satellite Coincidence: 0022Z, 0159Z, 1956Z, 2133Z QC notes: 0146-0156Z: weak AP is beyond 150 km and therefore not a concern 0206-0857Z: weak/moderate/intense AP and/or chaff echo remaining. All precip present is beyond 150 km. Chaff echo looked like real stratiform precip at first but "turns into" characteristic chaff appearance once nearing the radar which cinched it. Chaff echo moves with upper level wind pattern and confirmed by lack of clouds from archived satellite image. Radar in precip mode early in chaff's lifetime on the scope but that was due to cells still present on extreme eastern edge of scope and once this precip is gone, radar moves into clear-air mode...another chaff signature. -----> corrected ************************************************************************************************************* 22 Mar 98: No precipitation on this day. Data processed: 0006-2359 Z Satellite Coincidence: 0046Z, 0223Z, 2020Z, 2334Z QC notes: 1548-1854Z: chaff echo remaining -----> corrected. Verified as chaff and removed ************************************************************************************************************* 23 Mar 98: Only precipitation on this day in the form of widely scattered and intermittent cells off the coast after 12Z. Data processed: 0009-2358 Z Satellite Coincidence: 0111Z, 1908Z, 2045Z, 2358Z QC notes: 0107-0552Z: weak chaff echo remaining S of radar -----> corrected. Verified as chaff and removed. 0701-1155Z: weak chaff echo remaining S of radar -----> corrected. Verified as chaff and removed. ************************************************************************************************************** 24 Mar 98: No precipitation on this day. Data processed: 0007-2351 Z Satellite Coincidence: 0135Z, 1756Z, 1932Z, 2246Z QC notes: 0403-0759Z: scattered weak AP remaining -----> corrected 0947-1352Z: scattered to widespread weak/moderate AP remaining -----> corrected 1501-1758Z: weak chaff echo remaining N of the radar -----> corrected. Verified as chaff and removed. 1857-2054Z: chaff echo remaining N of the radar -----> corrected. Verified as chaff and removed. 2252-2351Z: weak AP N of radar and chaff W of radar remaining -----> corrected *************************************************************************************************************** 25 Mar 98: Only significant precipitation on this day is in the form of a small cluster of showers with some stronger embedded cells, NE of the radar from 15-21Z. Data processed: 0000-2353 Z Satellite Coincidence: 0022Z, 1820Z(55 km), 1956Z, 2310Z QC notes: 0050-0703Z: widespread weak AP remaining (no precip present within 150 km) -----> corrected 0851Z: moderate AP splotch remaining (no precip present) -----> corrected 1039-1325Z: scattered weak/moderate AP remaining (no precip within 150 km) -----> corrected 1454Z: horrendously intense radial spike remnants 3A !!FLAG!! -----> could not remove spike without removing precip....the good news is that only a ~25% of the remaining spike is within 150 km of the radar so it looks much worse than it actually is. 1622-2156Z: removal of light precipitation plus chaff echo present, in same vicinity (sticky situation) -----> light precip problem corrected but various other complications lead to different flags...let me outline each one at a time: 2B !!FLAG!! 1622-1741Z: no chaff present yet and minor flag was due to re-introduction of weak AP splotches west of the radar. This AP could not be removed without removing precip. 1B !!FLAG!! 1751-1850Z: satellite coincident VOS's still contain the weak AP west of of the radar which could not be removed without removing precip as well. Chaff begins to make itself present on the backside of the precip but is still out of range and therefore not a concern (see next flag for explanation of chaff presence on this day) 2A !!FLAG!! 1859-2156Z: weak AP west of radar still present and chaff is also now present within range....which is the reason for the major flag. Here is my reasoning which leads me to believe the SE moving reflectivity shield is chaff: (1) moves independently of the precip shield located in the same vicinity. Precip tracks WSW while chaff cloud moves southward (2) the 18Z visible satellite image for this day distinctly shows the clouds associated with the precipitation NE of KMLB. However the 980326_00Z IR satellite image shows no clouds in the vicinity of central Florida, even though considerable chaff is still present. (3) the composite radar image for 18Z distinctly shows the precip present NE of KMLB. However, once the precip is ogone (~21Z), none oft the echo believed to be chaff shows up in the mosaic..another criterion satisfied. (4) radar operated in clear-air mode (5) displays characteristic chaff echo in that it elongates into a streamer and is very shallow and weak 2206-2225Z: chaff echo remaining (no precip present) -----> corrected 2235-2353Z: chaff echo present along with precipitation 2B !!FLAG!! -----> could not remove chaff echo without removing light showers SE of radar. The good news though is that the chaff which remains is very weak and of very little areal coverage. In addition, some of the chaff which remains is beyond 150 km and not a concern....all this adds up to just a minor flag. *************************************************************************************************************** 26 Mar 98: Only precipitation on this day occurs as widely scattered, weak showers moving onshore south of the radar early on and scattered weak showers moving onshore after 13Z through the end of the day. Data processed: 0004-2356 Z Satellite Coincidence: 0046Z, 1707Z, 1843Z, 2334Z QC notes: 0004-0221Z: chaff NE of radar and weak AP remaining W of radar are both beyond 150 km (confirmed by 2A-54 convective/stratiform image generation) and therefore not a concern except for the following VOS's in this time period listed below. 0053-0103Z: weak AP splotch remaining within 150 km -----> corrected 0231-0854Z: chaff echo and weak AP remaining (no precip present) -----> corrected 1249-1724Z: removal of light precipitation (note: that the chaff echo which begins entering the scope towards the end of this time period is still beyond 150 km and therfore not a concern) 2B-,3B- !!flag!! -----> precip removal problem corrected. The very minor (and I mean VERY) flag is for the two or three small weak specks which look suspicious and may or may not be precipitation....not a big concern at all 1734-2356Z: removal of light precipitation coupled with significant chaff echo remaining (this is not going to be pretty) 2A+,1A+ !!FLAG!! -----> the small ounce of good news is that the small showers which were erroneously removed were successfully re-introduced. The bad news is the incredible amount of chaff return which remains and can not be removed without removing the light showers that are present. The echo considered chaff was confirmed with satellite imagery and archived radar mosaic images. This time period is a lost cause because the amount of chaff present possesses at least three times the areal coverage of the showers in the scope at the same time. I feel compelled to just blow everything away, including the showers but the VOS's would still be considered lost causes because of this precip removal. All I can do is give it the biggest major flag and possible and move on. *************************************************************************************************************** 27 Mar 98: Light showers push W from the Atlantic 00 ~ 06Z. Typical daytime showers develop over land around 15Z and continue through 23Z. A more ogranized line of showers / t-showers moves N of radar from 17Z ~ 23Z. Additional shower activity developes in the Atlantic and pushes toward the FL coast through the end of the day. Data Processed: 0007-2359Z Satellite Coincidence: 1731Z, 1907Z, 2044Z, 2221Z QC notes: 0007-0639Z: Light showers removed by default qc params. Also, some scattered AP remnants W of radar. ----> Some light showers reinstated, but it was more important in this case to remove most of the AP. However, a large time period (below) must be flagged. 2A,3A !!FLAG!! 0007-0421Z: AP cannot be totally removed due to the presence of light precip. 1509-2359Z: Light showers removed by default qc params. ----> Corrected - most shower activity reinstated while clutter and AP were suppressed. ************************************************************************************** 28 Mar 98: Light / Moderate shower activity developes into a convective line as the day progresses. Most activity slowly developes in the Atlantic or right on the coastline and propogates NW. Near the end of the day, scattered convection developes W of radar. Data Processed: 0009-2359Z Satellite Coincidence: 1618Z, 1754Z, 2108Z, 2245Z QC notes: 0009-0217Z: Light showers removed by default qc params. Also, AP remnants W of radar at far range. ----> Corrected - Most light showers reinstated while AP removed 0226-0622Z: Light AP remnants W of radar at far range (light precip E of radar at far range) ----> Corrected - AP totally removed except for a small patch beyond 150 km at 0325Z. A couple minor showers were removed in the process, but they were at far range. 0631-2134Z: Light showers removed by default qc params. ----> Corrected - Most shower activity reinstated. Showers could not be totally reinstated due to AP suppression. The showers which were not reinstated were minor in intensity with small coverage. 2339-2359Z: Light showers removed by default qc params. ----> Corrected - shower activity reinstated. ************************************************************************************** 29 Mar 98: Scattered convection over land (W of radar) 0005 ~ 05Z. Light showers pushing in from the Atlantic 2234-2352Z Data Processed: 0005-2352Z Satellite Coincidence: 1642Z, 1819Z, 1956Z, 2133Z QC notes: 0005-0434Z: Minor AP patches near convective activity ----> Corrected - AP removed 1110-1248Z: 1438Z: 2011-2021Z: 2106Z: These time periods have scattered AP (no precip) ----> Corrected - AP removed 2234-2352Z: Light showers (far range) removed by default qc params. ----> Corrected - showers reinstated. 2333Z: AP W of radar well beyond 150 km range - no flag required *************************************************************************************************************** 30 Mar 98: Light shower activity moves W from the Atlantic during the first 12 hrs of the day (no data after 12Z) Data Processed: 0003-1154Z Satellite Coincidence: 1530Z, 1706Z, 2020Z, 2157Z QC notes: 0003-1154Z: Light showers removed by default qc params during entire period. Widespread light AP over land (some probably due to birds ~ 11Z) ----> Most shower activity reinstated, however AP cannot be entirely removed due to the presence of light precip. Therefore, large time periods must be flagged (see below). 2A,3A !!FLAG!! 0052-0603Z: AP over land cannot be removed due to presence of light precip. 3B !!FLAG!! 1124-1129Z: Light AP SW of radar cannot be removed due to presence of light precip. **************************************************************************************************************** 31 Mar 98: Light shower activity moves NW from the Atlantic in the 4 hours of available data. Data Processed: 1218-1553Z Satellite Coincidence: 1418Z, 1554Z, 1908Z,2044Z QC notes: 1218-1553Z: Light showers removed by default qc params during entire period ----> Corrected - all precip restored Some minor clutter specks were reinstated with the showers, but they are too minor to flag the affected VOSs. ****************************************************************************************************************